Electrically powered surgical instrument with manual release

ABSTRACT

A surgical device comprising a surgical end effector, an actuation assembly having a part operable to move between a first position and a second position, an electrically-powered motor, a transmission mechanically connecting the motor to the part and being operable to selectively displace the part between the first and second positions when the motor is operated, and a manual release mechanically coupled to the transmission to selectively interrupt the transmission and, during interruption, displace the part towards the first position independent of operation of the motor.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is:

-   -   a divisional of U.S. patent application Ser. No. 16/390,570,        filed on Apr. 22, 2019, which is:        -   a divisional of U.S. patent application Ser. No. 15/385,385,            filed on Dec. 20, 2016, now U.S. Pat. No. 10,314,583, issued            on Jun. 11, 2019, which is:            -   a continuation of U.S. patent application Ser. No.                14/141,563, filed on Dec. 27, 2013, now U.S. Pat. No.                9,554,803, issued on Jan. 31, 2017, which is:                -   a divisional of U.S. patent application Ser. No.                    13/089,041, filed on Apr. 18, 2011, now U.S. Pat.                    No. 8,672,951, issued on Mar. 18, 2014, which is:                -    a divisional of U.S. patent application Ser. No.                    12/245,017, filed on Oct. 3, 2008, now U.S. Pat. No.                    7,959,050, issued on Jun. 14, 2011, which claims                    priority to U.S. Provisional Patent Application No.                    60/977,489, filed on Oct. 4, 2007;                -   a continuation-in-part of U.S. patent application                    Ser. No. 12/034,320, filed on Feb. 20, 2008, now                    U.S. Pat. No. 8,627,995, issued on Jan. 14, 2014,                    which:                -    claims priority to U.S. Provisional Patent                    Application No. 60/902,534, filed on Feb. 21, 2007;                    and                -    claims priority to U.S. Provisional Patent                    Application No. 60/977,489, filed on Oct. 4, 2007;                -   a continuation-in-part of U.S. patent application                    Ser. No. 13/847,971, filed on Mar. 20, 2013, now                    U.S. Pat. No. 9,901,340, issued on Feb. 27, 2018;                -   a continuation-in-part of U.S. patent application                    Ser. No. 13/798,369, filed on Mar. 13, 2013, now                    U.S. Pat. No. 9,622,744, issued on Apr. 18, 2017;                -   a continuation-in-part of U.S. patent application                    Ser. No. 13/743,179, filed on Jan. 16, 2013, now                    U.S. Pat. No. 8,844,791, issued on Sep. 30, 2014;                -   a continuation-in-part of U.S. patent application                    Ser. No. 13/622,819, filed on Sep. 19, 2012, now                    U.S. Pat. No. 9,687,234, issued on Jun. 27, 2017,                    which is:                -    a divisional of U.S. patent application Ser. No.                    13/229,076, filed on Sep. 9, 2011, now U.S. Pat. No.                    8,292,157, issued on Oct. 23, 2012;                -   a continuation-in-part of U.S. patent application                    Ser. No. 12/793,962, filed on Jun. 4, 2010, now U.S.                    Pat. No. 9,681,873, issued on Jun. 20, 2017;                -   a continuation-in-part of U.S. patent application                    Ser. No. 12/612,525, filed on Nov. 4, 2009, now U.S.                    Pat. No. 8,627,993, issued on Jan. 14, 2014, which                    is:                -    a divisional of U.S. patent application Ser. No.                    12/102,464, filed on Apr. 14, 2008, now U.S. Pat.                    No. 8,286,846, issued on Oct. 16, 2012;                -    a divisional of U.S. patent application Ser. No.                    12/102,181, filed on Apr. 14, 2008, now U.S. Pat.                    No. 8,573,459, issued on Nov. 5, 2013;                -    a divisional of U.S. patent application Ser. No.                    11/705,381, filed on Feb. 12, 2007, now U.S. Pat.                    No. 8,038,046, issued on Oct. 18, 2011, which:                -     claims priority to U.S. Provisional Patent                    Application No. 60/801,989, filed on May 19, 2006;                -     claims priority to U.S. Provisional Patent                    Application No. 60/810,272, filed on Jun. 2, 2006;                    and                -     claims priority to U.S. Provisional Patent                    Application No. 60/858,112, filed on Nov. 9, 2006;                -    a divisional of U.S. patent application Ser. No.                    11/705,334, filed on Feb. 12, 2007, now U.S. Pat.                    No. 8,573,462, issued on Nov. 5, 2013; and                -    a divisional of U.S. patent application Ser. No.                    11/705,246, filed on Feb. 12, 2007, now U.S. Pat.                    No. 8,028,885, issued on Oct. 4, 2011;                -   a continuation-in-part of U.S. patent application                    Ser. No. 13/654,073, filed on Oct. 17, 2012, now                    U.S. Pat. No. 9,855,038, issued on Jan. 2, 2018;                -   a continuation-in-part of U.S. patent application                    Ser. No. 13/547,968, filed on Jul. 12, 2012, now                    U.S. Pat. No. 8,695,865, issued on Apr. 15, 2014;                -   a continuation-in-part of U.S. patent application                    Ser. No. 13/228,933, filed on Sep. 9, 2011, now U.S.                    Pat. No. 8,920,435, issued on Dec. 30, 2014, which                    is:                -    a divisional of U.S. patent application Ser. No.                    12/633,292, filed on Dec. 8, 2009, now U.S. Pat. No.                    8,034,077, issued on Oct. 11, 2011, which is:                -     a divisional of U.S. patent application Ser. No.                    12/139,142, filed on Jun. 13, 2008, now U.S. Pat.                    No. 8,245,898, issued on Aug. 21, 2012, which is:                -      a divisional of U.S. patent application Ser. No.                    11/844,406, filed on Aug. 24, 2007, now U.S. Pat.                    No. 7,419,080, issued on Sep. 2, 2008; and                -      a divisional of U.S. patent application Ser. No.                    11/540,255, filed on Sep. 29, 2006, now U.S. Pat.                    No. 7,404,508, issued on Jul. 29, 2008; and                -   a continuation-in-part of U.S. patent application                    Ser. No. 11/541,105, filed on Sep. 29, 2006, which                    is:                -    a divisional of U.S. patent application Ser. No.                    11/491,626, filed on Jul. 24, 2006, now U.S. Pat.                    No. 8,579,176, issued on Nov. 12, 2013, which:                -     claims priority to U.S. Provisional Patent                    Application No. 60/702,643, filed on Jul. 26, 2005;                -     claims priority to U.S. Provisional Patent                    Application No. 60/760,000, filed on Jan. 18, 2006;                    and                -     claims priority to U.S. Provisional Patent                    Application No. 60/811,950, filed on Jun. 8, 2006,                    wherein the present application claims priority to                    each of the above-mentioned applications and the                    entire disclosures of all of these applications are                    hereby incorporated herein by reference in their                    entireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

n/a

FIELD OF THE INVENTION

The invention lies in the field of surgical instruments, in particularbut not necessarily, stapling devices. The stapling device described inthe present application is a hand-held, fully electrically self-poweredand controlled surgical stapler with a manual release.

BACKGROUND OF THE INVENTION

Medical stapling devices exist in the art. Ethicon Endo-Surgery, Inc. (aJohnson & Johnson company; hereinafter “Ethicon”) manufactures and sellssuch stapling devices. Circular stapling devices manufactured by Ethiconare referred to under the trade names PROXIMATE® PPH, CDH, and ILS andlinear staplers are manufactured by Ethicon under the trade namesCONTOUR and PROXIMATE. In each of these exemplary surgical staplers,tissue is compressed between a staple cartridge and an anvil and, whenthe staples are ejected, the compressed tissue is also cut. Dependingupon the particular tissue engaged by the physician, the tissue can becompressed too little (where blood color is still visibly present in thetissue), too much (where tissue is crushed), or correctly (where theliquid is removed from the tissue, referred to as dessicating orblanching).

Staples to be delivered have a given length and the cartridge and anvilneed to be within an acceptable staple firing distance so that thestaples close properly upon firing. Therefore, these staplers havedevices indicating the relative distance between the two planes andwhether or not this distance is within the staple length firing range.Such an indicator is mechanical and takes the form of a sliding barbehind a window having indicated thereon a safe staple-firing range.These staplers are all hand-powered, in other words, they requirephysical actuations by the user/physician to position the anvil andstapler cartridge about the tissue to be stapled and/or cut, to closethe anvil and stapler cartridge with respect to one another, and to fireand secure the staples at the tissue (and/or cut the tissue). No priorart staplers are electrically powered to carry out each of theseoperations because the longitudinal force necessary to effect staplefiring is typically on the order of 250 pounds at the staple cartridge.Further, such staplers do not have any kind of active compressionindicator that would optimizes the force acting upon the tissue that isto be stapled so that tissue degradation does not occur.

One hand-powered, intraluminal anastomotic circular stapler is depicted,for example, in U.S. Pat. No. 5,104,025 to Main et al., and assigned toEthicon. Main et al. is hereby incorporated herein by reference in itsentirety. As can be seen most clearly in the exploded view of FIG. 7 inMain et al., a trocar shaft 22 has a distal indentation 21, somerecesses 28 for aligning the trocar shaft 22 to serrations 29 in theanvil and, thereby, align the staples with the anvils 34. A trocar tip26 is capable of puncturing through tissue when pressure is appliedthereto. FIGS. 3 to 6 in Main et al. show how the circular stapler 10functions to join two pieces of tissue together. As the anvil 30 ismoved closer to the head 20, interposed tissue is compressedtherebetween, as particularly shown in FIGS. 5 and 6 . If this tissue isovercompressed, the surgical stapling procedure might not succeed. Thus,it is desirable to not exceed the maximum acceptable tissue compressionforce. The interposed tissue can be subject to a range of acceptablecompressing force during surgery. This range is known and referred to asoptimal tissue compression or OTC, and is dependent upon the type oftissue being stapled. While the stapler shown in Main et al. does have abar indicator that displays to the user a safe staple-firing distancebetween the anvil and the staple cartridge, it cannot indicate to theuser any level of compressive force being imparted upon the tissue priorto stapling. It would be desirable to provide such an indication so thatover-compression of the tissue can be avoided.

SUMMARY OF THE INVENTION

The systems, apparatuses, and methods described herein overcome theabove-noted and other deficiencies of the prior art by providing aelectrically self-powered surgical device that uses the self-power toeffect a medical procedure. For example, in a linear endocutter, theelectric on-board power can position an anvil and stapler cartridge withrespect to one another about tissue to be stapled and/or cut, and, afterclosing the anvil and stapler cartridge with respect to one another,firing and securing the staples at the tissue (and/or cutting thetissue). Further, the electrically self-powered surgical device canindicate to the user a user-pre-defined level of compressive force beingimparted upon the tissue prior to firing the staples. Also provided aremethods for operating the electric surgical stapling device to staplewhen optimal tissue compression (OTC) exists. Further provided is amanual release device that allows recovery from a partial actuation or ajam.

An offset-axis configuration for the two anvil and staple firingsub-assemblies creates a device that can be sized to comfortably fitinto a user's hand. It also decreases manufacturing difficulty byremoving previously required nested (co-axial) hollow shafts. With theaxis of the anvil sub-assembly being offset from the staple firingsub-assembly, the length of the threaded rod for extending andretracting the anvil can be decreased by approximately two inches,thereby saving in manufacturing cost and generating a shorterlongitudinal profile.

An exemplary method for using the electric stapler includes a power-onfeature that permits entry into a manual mode for testing purposes. In asurgical procedure, the stapler is a one-way device. In the test mode,however, the user has the ability to move the trocar back and forth asdesired. This test mode can be disengaged and the stapler reset to theuse mode for packaging and shipment. For packaging, it is desirable (butnot necessary) to have the anvil be at a distance from the staplecartridge. Therefore, a homing sequence can be programmed to place theanvil 1 cm (for example) away from the staple cartridge before poweringdown for packaging and shipment. Before use, the trocar is extended andthe anvil is removed. If the stapler is being used to dissect a colon,for example, the trocar is retracted back into the handle and the handleis inserted trans-anally into the colon to downstream side of thedissection while the anvil is inserted through a laparoscopic incisionto an upstream side of the dissection. The anvil is attached to thetrocar and the two parts are retracted towards the handle until a stapleready condition occurs. The staple firing sequence is started, which canbe aborted, to staple the dissection and simultaneously cut tissue atthe center of the dissection to clear an opening in the middle of thecircular ring of staples. The staple firing sequence includes an optimaltissue compression (OTC) measurement and feedback control mechanism thatcauses staples to be fired only when the compression is in a desiredpressure range, referred to as the OTC range. This range or value isknown beforehand based upon known characteristics of the tissue to becompressed between the anvil and staple cartridge.

Some exemplary procedures in which the electric stapler can be usedinclude colon dissection and gastric bypass surgeries. There are manyother uses for the electric stapler in various different technologyareas.

With the foregoing and other objects in view, there is provided asurgical device that comprises a surgical end effector, an actuationassembly having a part operable to move between a first position and asecond position, an electrically-powered motor, a transmissionmechanically connecting the motor to the part and being operable toselectively displace the part between the first and second positionswhen the motor is operated, and a manual release mechanically coupled tothe transmission to selectively interrupt the transmission and, duringinterruption, displace the part towards the first position independentof operation of the motor.

In accordance with a mode of an exemplary embodiment thereof, the firstposition is a starting position and the second position is an actuatedposition in which the part actuates the surgical end effector.

In accordance with another mode of an exemplary embodiment thereof, thetransmission is operable to selectively displace the part to any pointbetween the first position and the second position when the motor isoperated.

In accordance with a further mode of an exemplary embodiment thereof,the surgical device further comprises a controller electricallyconnected to the motor and selectively operating the motor.

In accordance with an additional mode of an exemplary embodimentthereof, the surgical end effector is a stapling end effector.

In accordance with an added mode of an exemplary embodiment thereof, themanual release is mechanically disposed in the transmission.

Other embodiments include a method for operating a surgical instrument,which comprises: mechanically coupling a manual release to atransmission of the surgical instrument, the surgical instrument havinga surgical end effector and an actuation assembly, wherein thetransmission translates movement of an electrically-powered motor of thedevice to movement of a part of the actuation assembly and the part isoperable to move between a first position and a second position; andselectively interrupting the transmission with the manual release tomove the part towards the first position independent of operation of themotor.

Other features that are considered as characteristic for the systems,apparatuses, and methods described herein are set forth in the appendedclaims.

Although the systems, apparatuses, and methods are illustrated anddescribed herein as embodied in an electrically powered surgicalinstrument with manual release, it is, nevertheless, not intended to belimited to the details shown because various modifications andstructural changes may be made therein without departing from the spiritof the invention and within the scope and range of equivalents of theclaims.

The construction and methods of operation, however, together withadditional objects and advantages thereof, will be best understood fromthe following description of specific embodiments when read inconnection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of embodiments of the invention will be apparent from thefollowing detailed description of the exemplary embodiments thereof,which description should be considered in conjunction with theaccompanying drawings in which:

FIG. 1 is a perspective view from a side of an exemplary embodiment ofan electric stapler;

FIG. 2 is a fragmentary side elevational view of the stapler of FIG. 1with a right half of a handle body and with a proximal backbone plateremoved;

FIG. 3 is an exploded, perspective view of an anvil control assembly ofthe stapler of FIG. 1 ;

FIG. 4 is an enlarged, fragmentary, exploded, perspective view of theanvil control assembly of FIG. 3 ;

FIG. 5 is a fragmentary, perspective view of a staple firing controlassembly of the stapler of FIG. 1 from a rear side thereof;

FIG. 6 is an exploded, perspective view of the staple firing controlassembly of the stapler of FIG. 1 ;

FIG. 7 is an enlarged, fragmentary, exploded, perspective view of thestaple firing control assembly of FIG. 6 ;

FIG. 8 is a fragmentary, horizontally cross-sectional view of the anvilcontrol assembly from below the handle body portion of the stapler ofFIG. 1 ;

FIG. 9 is a fragmentary, enlarged, horizontally cross-sectional viewfrom below a proximal portion of the anvil control assembly FIG. 8 ;

FIG. 10 is a fragmentary, enlarged, horizontally cross-sectional viewfrom below an intermediate portion of the anvil control assembly of FIG.8 ;

FIG. 11 is a fragmentary, enlarged, horizontally cross-sectional viewfrom below a distal portion of the anvil control assembly of FIG. 8 ;

FIG. 12 is a fragmentary, vertically cross-sectional view from a rightside of a handle body portion of the stapler of FIG. 1 ;

FIG. 13 is a fragmentary, enlarged, vertically cross-sectional view fromthe right side of a proximal handle body portion of the stapler of FIG.12 ;

FIG. 14 is a fragmentary, enlarged, vertically cross-sectional view fromthe right side of an intermediate handle body portion of the stapler ofFIG. 12 ;

FIG. 15 is a fragmentary, further enlarged, vertically cross-sectionalview from the right side of the intermediate handle body portion of thestapler of FIG. 14 ;

FIG. 16 is a fragmentary, enlarged, vertically cross-sectional view fromthe right side of a distal handle body portion of the stapler of FIG. 12;

FIG. 17 is a perspective view of a portion of an anvil of the stapler ofFIG. 1 ;

FIG. 18 is a fragmentary, cross-sectional view of a removable staplingassembly including the anvil, a stapler cartridge, a force switch, and aremovable cartridge connecting assembly of the stapler of FIG. 1 ;

FIG. 19 is a fragmentary, horizontally cross-sectional view of the anvilcontrol assembly from above the handle body portion of the stapler ofFIG. 1 with the anvil rod in a fully extended position;

FIG. 20 is a fragmentary, side elevational view of the handle bodyportion of the stapler of FIG. 1 from a left side of the handle bodyportion with the left handle body and the circuit board removed and withthe anvil rod in a fully extended position;

FIG. 21 is a fragmentary, side elevational view of the handle bodyportion of the stapler of FIG. 20 with the anvil rod in a 1-cm anvilclosure position;

FIG. 22 is a fragmentary, horizontally cross-sectional view of the anvilcontrol assembly from above the handle body portion of the stapler ofFIG. 1 with the anvil rod in a safe staple firing position;

FIG. 23 is a fragmentary, horizontally cross-sectional view of the anvilcontrol assembly from above the handle body portion of the stapler ofFIG. 1 with the anvil rod in a fully retracted position;

FIG. 24 is a fragmentary, horizontally cross-sectional view of thefiring control assembly from above the handle body portion of thestapler of FIG. 1 ;

FIG. 25 is a fragmentary, enlarged, horizontally cross-sectional viewfrom above a proximal portion of the firing control assembly of FIG. 24;

FIG. 26 is a fragmentary, enlarged, horizontally cross-sectional viewfrom above an intermediate portion of the firing control assembly ofFIG. 24 ;

FIG. 27 is a fragmentary, enlarged, horizontally cross-sectional viewfrom above a distal portion of the firing control assembly of FIG. 24 ;

FIGS. 28 and 29 are shaded, fragmentary, enlarged, partially transparentperspective views of a staple cartridge removal assembly of the staplerof FIG. 1 ;

FIG. 30 is a schematic circuit diagram of an exemplary encryptioncircuit for interchangeable parts of the medical device;

FIG. 31 is a bar graph illustrating a speed that a pinion moves a rackshown in FIG. 32 for various loads;

FIG. 32 is a fragmentary, perspective view of a simplified, exemplaryportion of a gear train between a gear box and a rack;

FIG. 33 is a fragmentary, vertically longitudinal, cross-sectional viewof a distal end of an articulating portion of an exemplary embodiment ofan end effector with the inner tube, the pushrod-blade support, theanvil, the closure ring, and the near half of the staple sled removed;

FIG. 34 is a schematic circuit diagram of an exemplary switchingassembly for a power supply;

FIG. 35 is a schematic circuit diagram of an exemplary switchingassembly for forward and reverse control of a motor;

FIG. 36 is a schematic circuit diagram of another exemplary switchingassembly for the power supply and the forward and reverse control of themotor;

FIG. 37 is a left side elevational view of the device with the outershell removed;

FIG. 38 is an enlarged left side elevational view of a portion thedevice of FIG. 37 with the left side frame removed;

FIG. 39 is a right side elevational view of the device of FIG. 37 ;

FIG. 40 is an enlarged right side elevational view of a portion thedevice of FIG. 38 with the right side frame removed;

FIG. 41 is a perspective view of the device portion of FIG. 40 from theright rear;

FIG. 42 is a rear elevational view of the device portion of FIG. 40 ;

FIG. 43 is a perspective view of the device portion of FIG. 40 from theleft rear with the first to third stage cover removed;

FIG. 44 is a perspective view of the device portion of FIG. 40 fromabove the right side with the power supply removed;

FIG. 45 is a perspective view of the device portion of FIG. 44 with themanual release lever in a first intermediate position with the castlegear in the separated position;

FIG. 46 is a perspective view of the device portion of FIG. 45 with themanual release lever in a second intermediate position;

FIG. 47 is a top plan view of the device portion of FIG. 46 with themanual release lever in a third intermediate position;

FIG. 48 is an enlarged perspective view of the manual release assemblyfrom the right side with the second stage release gear, two cam plates,and a pawl spring removed with the pawl in an upper, unratchetingposition;

FIG. 49 is a perspective view of the manual release lever from below aright front side;

FIG. 50 is a perspective view of the manual release lever from below aright rear side;

FIG. 51 is a perspective view of the manual release lever from below aleft rear side;

FIG. 52 is a perspective view of a cam plate from a left side;

FIG. 53 is a perspective view of a castle gear from a right side;

FIG. 54 is a perspective view of a fourth stage pinion from the leftside;

FIG. 55 is a perspective view of the device portion of FIG. 44 fromabove a front right side with a pawl against a pawl cam;

FIG. 56 is a perspective view of the device portion of FIG. 55 with thepawl off of the pawl cam and against a ratchet gear and with the castlegear in the separated position;

FIG. 57 is a perspective view of the device portion of FIG. 44 fromabove a front left side with the manual release in an intermediateposition;

FIG. 58 is a perspective view of the device portion of FIG. 57 with themanual release in another intermediate position;

FIG. 59 is an enlarged right side elevational view of a portion of thedevice of FIG. 40 with the end effector control handle in an unactuatedposition;

FIG. 60 is an enlarged right side elevational view of a the deviceportion of FIG. 59 with the end effector control handle in a partiallyactuated position;

FIG. 61 is an enlarged perspective view of a shaft connector portion ofthe device of FIG. 37 from above the front right side with a removableend effector shaft secured in a frame;

FIG. 62 is an enlarged perspective view of the shaft connector portionof FIG. 61 with shaft securing device removed to permit removal of theend effector shaft from the frame;

FIG. 63 is an elevational view of the interior of a left half of theouter shell of the device of FIG. 37 ;

FIG. 64 is an elevational view of the interior of a right half of theouter shell of the device of FIG. 37 ;

FIG. 65 is an elevational view of the exterior of the right half of theouter shell of the device of FIG. 37 ; and

FIG. 66 is an elevational view of the exterior of the left half of theouter shell of the device of FIG. 37 .

DETAILED DESCRIPTION OF THE INVENTION

Aspects of the described systems, apparatuses, and methods are disclosedin the following description and related drawings directed to specificembodiments. Alternate embodiments may be devised without departing fromthe spirit or the scope of the invention. Additionally, well-knownelements of exemplary embodiments of the invention will not be describedin detail or will be omitted so as not to obscure the relevant detailsof the invention.

Before the systems, apparatuses, and methods are disclosed anddescribed, it is to be understood that the terminology used herein isfor the purpose of describing particular embodiments only and is notintended to be limiting. It must be noted that, as used in thespecification and the appended claims, the singular forms “a,” “an,” and“the” include plural references unless the context clearly dictatesotherwise.

While the specification concludes with claims defining the features ofthe systems, apparatuses, and methods that are regarded as novel, it isbelieved that the systems, apparatuses, and methods will be betterunderstood from a consideration of the following description inconjunction with the drawing figures, in which like reference numeralsare carried forward. The figures of the drawings are not drawn to scale.Further, it is noted that the figures have been created using acomputer-aided design computer program. This program at times removescertain structural lines and/or surfaces when switching from a shaded orcolored view to a wireframe view. Accordingly, the drawings should betreated as approximations and be used as illustrative of the features ofthe disclosed systems, apparatuses, and methods.

Referring now to the figures of the drawings in detail and first,particularly to FIGS. 1 to 2 thereof, there is shown an exemplaryembodiment of an electric surgical circular stapler 1. The presentapplication applies the electrically powered handle to a circularsurgical staple head for ease of understanding only. The systems,apparatuses, and methods herein are not limited to circular staplers andcan be applied to any surgical stapling head, such as a linear staplingdevice, for example. Such an exemplary embodiment is described, inparticular, starting with FIG. 37 .

The powered stapler 1 has a handle body 10 containing three switches: ananvil open switch 20, an anvil close switch 21, and a staple firingswitch 22. Each of these switches is electrically connected to a circuitboard 500 (see FIG. 12 ) having circuitry programmed to carry out thestapling functions of the stapler 1. The circuit board 500 iselectrically connected to a power supply 600 contained within the handlebody 10. One exemplary embodiment utilizes 2 to 6 Lithium CR123 or CR2cells as the power supply 600. Other power supply embodiments arepossible, such as rechargeable batteries or a power converter that isconnected to an electric mains (in the latter embodiment, the staplerwould not be self-powered or self-contained). As used herein, the termsself-powered or self-contained when used with regard to the electricpower supply (600) are interchangeable and mean that the power supply isa complete and independent unit in and of itself and can operate underits own power without the use of external power sources. For example, apower supply having an electric cord that is plugged into an electricmains during use is not self-powered or self-contained.

Insulated conductive wires or conductor tracks on the circuit board 500connect all of the electronic parts of the stapler 1, such as an on/offswitch 12, a tissue compression indicator 14, the anvil and firingswitches 20, 21, 22, the circuit board 500, and the power supply 600,for example. But these wires and conductors are not shown in the figuresof the drawings for ease of understanding and clarity.

The distal end of the handle body 10 is connected to a proximal end of arigid anvil neck 30. Opposite this connection, at the distal end of theanvil neck 30, is a coupling device 40 for removably attaching a staplecartridge 50 and an anvil 60 thereto. Alternatively, the staplecartridge 50 can be non-removable in a single-use configuration of thestapler 1. These connections will be described in further detail below.

FIG. 2 shows the handle body 10 with the right half 13 of the handlebody 10 and the circuit board 500 removed. As will be discussed below, aproximal backbone plate 70 is also removed from the view of FIG. 2 toallow viewing of the internal components inside the handle body 10 fromthe right side thereof. What can be seen from the view of FIG. 2 is thatthere exist two internal component axes within the handle body 10. Afirst of these axes is the staple control axis 80, which is relativelyhorizontal in the view of FIG. 2 . The staple control axis 80 is thecenterline on which lie the components for controlling staple actuation.The second of these axes is the anvil control axis 90 and is disposed atan angle to the staple control axis 80. The anvil control axis 90 is thecenterline on which lie the components for controlling anvil actuation.It is this separation of axes 80, 90 that allows the electric stapler 1to be powered using a handle body 10 that is small enough to fit in aphysician's hand and that does not take up so much space that thephysician becomes restricted from movement in all necessary directionsand orientations.

Shown inside the handle body 10 is the on/off switch 12 (e.g., a grenadepin) for controlling power (e.g., battery power) to all of theelectrical components and the tissue compression indicator 14. Thetissue compression indicator 14 indicates to the physician that thetissue being compressed between the anvil 60 and the staple cartridge 50has or has not been compressed with greater than a pre-set compressiveforce, which will be described in further detail below. This indicator14 is associated with a force switch 400 that has been described inco-pending U.S. Patent Provisional Application Ser. No. 60/801,989 filedMay 19, 2006, and titled “Force Switch” (the entirety of which isincorporated by reference herein).

The components along the anvil control axis 90 make up the anvil controlassembly 100. An anvil control frame 110 is aligned along the anvilcontrol axis 90 to house and/or fix various part of the anvil controlassembly 100 thereto. The anvil control frame 110 has a proximal mount112, an intermediate mount 114, and a distal mount 116. Each of thesemounts 112, 114, 116 can be attached to or integral with the controlframe 110. In the exemplary embodiment, for ease of manufacturing, theproximal mount 112 has two halves and is separate from the frame 110 andthe intermediate mount 114 is separate from the frame 110.

At the proximal end of the anvil control assembly 100 is an anvil motor120. The anvil motor 120 includes the drive motor and any gearbox thatwould be needed to convert the native motor revolution speed to adesired output axle revolution speed. In the present case, the drivemotor has a native speed of approximately 10,000 rpm and the gearboxconverts the speed down to between approximately 50 and 70 rpm at anaxle 122 extending out from a distal end of the anvil motor 120. Theanvil motor 120 is secured both longitudinally and rotationally insidethe proximal mount 112.

A motor-shaft coupler 130 is rotationally fixed to the axle 122 so thatrotation of the axle 122 translates into a corresponding rotation of themotor coupler 130.

Positioned distal of the coupler 130 is a rotating nut assembly 140. Thenut assembly 140 is, in this embodiment, a two part device having aproximal nut half 141 and a distal nut half 142 rotationally andlongitudinally fixed to the proximal nut half 141. It is noted thatthese nut halves 141, 142 can be integral if desired. Here, they areillustrated in two halves for ease of manufacturing. The proximal end ofthe nut assembly 140 is rotationally fixed to the distal end of thecoupler 130. Longitudinal and rotational support throughout the lengthof these two connected parts is assisted by the intermediate 114 anddistal 116 mounts.

A proximal nut bushing 150 (see FIG. 3 ) is interposed between theintermediate mount 114 and the proximal nut half 141 and a distal nutbushing 160 is interposed between the distal mount 116 and the distalnut half 142 to have these parts spin efficiently and substantiallywithout friction within the handle body 10 and the anvil control frame110. The bushings 150, 160 can be of any suitable bearing material, forexample, they can be of metal such as bronze or a polymer such as nylon.To further decrease the longitudinal friction between the rotating nutassembly 140 and the coupler 130, a thrust washer 170 is disposedbetween the proximal bushing 150 and the proximal nut half 141.

Rotation of the coupler 130 and nut assembly 140 is used to advance orretract a threaded rod 180, which is the mechanism through which theanvil 60 is extended or retracted. The threaded rod 180 is shown infurther detail in the exploded view of FIGS. 3 to 4 and is described infurther detail below. A rod support 190 is attached to a distal end ofthe anvil control frame 110 for extending the supporting surfaces insidethe nut assembly 140 that keep the rod 180 aligned along the anvilcontrol axis 90. The rod support 190 has a smooth interior shapecorresponding to an external shape of the portion of the rod 180 thatpasses therethrough. This mating of shapes allows the rod 180 to moveproximally and distally through the support 190 substantially withoutfriction. To improve frictionless movement of the rod 180 through thesupport 190, in the exemplary embodiment, a cylindrical rod bushing 192is disposed between the support 190 and the rod 180. The rod bushing 192is not visible in FIG. 2 because it rests inside the support 190.However, the rod bushing 192 is visible in the exploded view of FIGS. 3to 4 . With the rod bushing 192 in place, the internal shape of thesupport 190 corresponds to the external shape of the rod bushing 192 andthe internal shape of the rod bushing 192 corresponds to the externalshape of the portion of the rod 180 that passes therethrough. The rodbushing 192 can be, for example, of metal such as bronze or a polymersuch as nylon.

The components along the staple control axis 80 form the staple controlassembly 200. The staple control assembly 200 is illustrated in FIG. 5viewed from a proximal upper and side perspective. The proximal end ofthe staple control assembly 200 includes a stapling motor 210. Thestapling motor 210 includes the drive motor and any gearbox that wouldbe needed to convert the native motor revolution speed to a desiredrevolution speed. In the present case, the drive motor has a nativespeed of approximately 20,000 rpm and the gearbox converts the speed toapproximately 200 rpm at an output axle 212 at the distal end of thegearbox. The axle 212 cannot be seen in the view of FIG. 5 but can beseen in the exploded view of FIGS. 6 to 7 .

The stapling motor 210 is rotationally and longitudinally fixed to amotor mount 220. Distal of the motor mount 220 is an intermediatecoupling mount 230. This coupling mount 230 has a distal plate 232 thatis shown, for example in FIG. 6 . The distal plate 232 is removable fromthe coupling mount 230 so that a rotating screw 250 can be heldtherebetween. It is this rotating screw 250 that acts as the drive forejecting the staples out of the staple cartridge 50. The efficiency intransferring the rotational movement of axle 212 to the rotating screw250 is a factor that can substantially decrease the ability of thestapler 1 to deliver the necessary staple ejection longitudinal force ofup to 250 pounds. Thus, an exemplary embodiment of the screw 250 has anacme profile thread.

There are two exemplary ways described herein for efficiently couplingthe rotation of the axle 212 to the screw 250. First, the stapling motor210 can be housed “loosely” within a chamber defined by the handle body10 so that it is rotationally stable but has play to move radially andso that it is longitudinally stable but has play to move. In such aconfiguration, the stapling motor 210 will “find its own center” toalign the axis of the axle 212 to the axis of the screw 250, which, inthe exemplary embodiment, is also the staple control axis 80.

A second exemplary embodiment for aligning the axle 212 and the screw250 is illustrated in FIGS. 1 to 5 , for example. In this embodiment, aproximal end of a flexible coupling 240 is fixed (both rotationally andlongitudinally) to the axle 212. This connection is formed by fittingthe distal end of the axle 212 inside a proximal bore 241 of theflexible coupling 240. See FIG. 12 . The axle 212 is, then, securedtherein with a proximal setscrew 213. The screw 250 has a proximalextension 251 that fits inside a distal bore 242 of the flexiblecoupling 240 and is secured therein by a distal setscrew 252. It isnoted that the figures of the drawings show the flexible coupling 240with ridges in the middle portion thereof. In an exemplary embodiment ofthe coupling 240, the part is of aluminum or molded plastic and has aspiral or helixed cut-out around the circumference of the center portionthereof. In such a configuration, one end of the coupling 240 can movein any radial direction (360 degrees) with respect to the other end (asin a gimbal), thus providing the desired flex to efficiently align thecentral axes of the axle 212 and the screw 250.

The proximal extension 251 of the screw 250 is substantially smaller indiameter than the diameter of the bore 231 that exists in and throughthe intermediate coupling mount 230. This bore 231 has two increasingsteps in diameter on the distal side thereof. The first increasing stepin diameter is sized to fit a proximal radius screw bushing 260, whichis formed of a material that is softer than the intermediate couplingmount 230. The proximal radius screw bushing 260 only keeps the screw250 axially aligned and does not absorb or transmit any of thelongitudinal thrust. The second increasing step in diameter is sized tofit a proximal thrust bearing 270 for the screw 250. In an exemplaryembodiment of the thrust bearing 270, proximal and distal platessandwich a bearing ball retainer plate and bearing balls therebetween.This thrust bearing 270 absorbs all of the longitudinal thrust that isimparted towards the axle 212 while the up to 250 pounds of longitudinalforce is being applied to eject the staples in the staple cartridge 50.The proximal extension 251 of the screw 250 has different sizeddiameters for each of the interiors of the screw bushing 260 and thethrust bearing 270. The motor mount 220 and the coupling mount 230,therefore, form the two devices that hold the flexible coupling 240therebetween.

The rotating screw 250 is held inside the distal plate 232 with a distalradius screw bushing 280 similar to the proximal radius screw bushing260. Thus, the screw 250 rotates freely within the distal plate 232. Totranslate the rotation of the screw 250 into a linear distal movement,the screw 250 is threaded within a moving nut 290. Movement of the nut290 is limited to the amount of movement that is needed for completeactuation of the staples; in other words, the nut 290 only needs to movethrough a distance sufficient to form closed staples between the staplecartridge 50 and the anvil 60 and to extend the cutting blade, if any,within the staple cartridge 50, and then retract the same. When the nut290 is in the proximal-most position (see, e.g., FIG. 12 ), the staplesare at rest and ready to be fired. When the nut 290 is in thedistal-most position, the staples are stapled through and around thetissue interposed between the staple cartridge 50 and the anvil, and theknife, if any, is passed entirely through the tissue to be cut. Thedistal-most position of the nut 290 is limited by the location of thedistal plate 232. Thus, the longitudinal length of the threads of thescrew 250 and the location of the distal plate 232 limit the distalmovement of the nut 290.

Frictional losses between the screw 250 and the nut 290 contribute to asignificant reduction in the total pounds of force that can betransmitted to the staple cartridge 50 through the cartridge plunger320. Therefore, it is desirable to select the materials of the screw 250and the nut 290 and the pitch of the threads of the screw 250 in anoptimized way. It has been found that use of a low-friction polymer formanufacturing the nut 290 will decrease the friction enough to transmitthe approximately 250 pounds of longitudinal force to the distal end ofthe cartridge plunger 320—the amount of force that is needed toeffectively deploy the staples. Two particular exemplary materialsprovide the desired characteristics and are referred to in the art asDELRIN® AF Blend Acetal (a thermoplastic material combining TEFLON®fibers uniformly dispersed in DELRIN® acetal resin) and RULON® (acompounded form of TFE fluorocarbon) or other similar low-frictionpolymers.

A nut coupling bracket 300 is longitudinally fixed to the nut 290 sothat it moves along with the nut 290. The nut coupling bracket 300provides support for the relatively soft, lubricious nut material. Inthe exemplary embodiment shown, the bracket 300 has an interior cavityhaving a shape corresponding to the exterior shape of the nut 290. Thus,the nut 290 fits snugly into the coupling bracket 300 and movement ofthe nut 290 translates into a corresponding movement of the nut couplingbracket 300. The shape of the nut coupling bracket 300 is, in theexemplary embodiment, dictated by the components surrounding it and bythe longitudinal forces that it has to bear. For example, there is aninterior cavity 302 distal of the nut 290 that is shaped to receive thedistal plate 232 therein. The nut coupling bracket 300 also has a distalhousing 304 for receiving therein a stiffening rod 310. The stiffeningrod 310 increases the longitudinal support and forms a portion of theconnection between the nut 290 and a cartridge plunger 320 (see, i.e.,FIG. 5 ), which is the last moving link between elements in the handlebody 10 and the staple cartridge 50. A firing bracket 330, disposedbetween the distal end of the nut coupling bracket 300 and thestiffening rod 310, strengthens the connection between the nut couplingbracket 300 and the rod 310.

Various components of the stapler 1 are connected to one another to forma backbone or spine. This backbone is a frame providingmulti-directional stability and is made up of four primary parts (inorder from proximal to distal): the anvil control frame 110, theproximal backbone plate 70 (shown in FIGS. 3 to 4 and 6 to 7 ), a distalbackbone plate 340, and the anvil neck 30. Each of these four parts islongitudinally and rotationally fixed to one another in this order andforms the skeleton on which the remainder of the handle components isattached in some way. Lateral support to the components is provided bycontours on the inside surfaces of the handle body 10, which in anexemplary embodiment is formed of two halves, a left half 11 and a righthalf 13. Alternatively, support could be single frame, stamped, orincorporated into the handle halves 11, 13.

Functionality of the anvil control assembly 100 is described with regardto FIGS. 17 to 27 . To carry out a stapling procedure with the stapler1, the anvil 60 is removed entirely from the stapler 1 as shown in FIG.17 . The anvil open switch 20 is depressed to extend the distal end ofthe trocar tip 410 housed within the staple cartridge and which islongitudinally fixedly connected to the screw 250. The point of thetrocar tip 410 can, now, be passed through or punctured through tissuethat is to be stapled. The user can, at this point, replace the anvil 60onto the trocar tip 410 from the opposite side of the tissue (see FIG.18 ) and, thereby, lock the anvil 60 thereon. The anvil closed switch 22can be actuated to begin closing the anvil 60 against the staplecartridge 50 and pinch the tissue therebetween within an anvil-cartridgegap 62.

To describe how the trocar tip controlling movement of the anvil 60occurs, reference is made to FIGS. 8 to 10, 14 to 15, and 18 . As shownin dashed lines in FIG. 15 , a rod-guiding pin 143 is positioned withinthe central bore 144 of the distal nut half 142. As the threaded rod 180is screwed into the rotating nut 140, 141, 142, the pin 143 catches theproximal end of the thread 182 to surround the pin 143 therein. Thus,rotation of the nut 140 with the pin 143 inside the thread 182 willcause proximal or distal movement of the rod 180, depending on thedirection of nut rotation. The thread 182 has a variable pitch, as shownin FIGS. 14 to 15 , to move the anvil 60 at different longitudinalspeeds. When the pin 143 is inside the longer (lower) pitched threadportion 183, the anvil 60 moves longitudinally faster. In comparison,when the pin 143 is inside the shorter (higher) pitched thread portion184, the anvil 60 moves longitudinally slower. It is noted that the pin143 is the only portion contacting the thread 182 when in the longerpitched thread portion 183. Thus, the pin 143 is exposed to the entirelongitudinal force that is acting on the rod 180 at this point in time.The pin 143 is strong enough to bear such forces but may not besufficient to withstand all longitudinal force that could occur withanvil 60 closure about interposed tissue.

As shown in FIG. 14 , the rod 180 is provided with a shorter pitchedthread portion 184 to engage in a corresponding internal thread 145 atthe proximal end of the central bore 144 of the proximal nut half 141.When the shorter pitched thread portion 184 engages the internal thread145, the entire transverse surface of the thread portion 184 contactsthe internal thread 145. This surface contact is much larger than thecontact between the pin 143 and any portion of the thread 182 and,therefore, can withstand all the longitudinal force that occurs withrespect to anvil 60 closure, especially when the anvil 60 is closingabout tissue during the staple firing state. For example, in theexemplary embodiment, the pin 143 bears up to approximately 30 to 50pounds of longitudinal force. This is compared to the threads, which canhold up to 400 pounds of longitudinal force—an almost 10-to-1difference.

An alternative exemplary embodiment of anvil control assembly 100 canentirely remove the complex threading of the rod 180. In such a case,the rod 180 has a single thread pitch and the anvil motor 120 is driven(through corresponding programming in the circuit board 500) atdifferent speeds dependent upon the longitudinal position of thesingle-thread rod 180.

In any embodiment for driving the motors 120, 210, the controlprogramming can take many forms. In one exemplary embodiment, themicrocontroller on the battery powered circuit board 500 can apply pulsemodulation (e.g., pulse-width, pulse-frequency) to drive either or bothof the motors. Further, because the stapler 1 is a device that has a lowduty cycle, or is a one-use device, components can be driven to exceedacceptable manufacturers' specifications. For example, a gear box can betorqued beyond its specified rating. Also, a drive motor, for example, a6 volt motor, can be overpowered, for example, with 12 volts.

Closure of the anvil 60 from an extended position to a position in whichthe tissue is not compressed or is just slightly compressed can occurrapidly without causing damage to the interposed tissue. Thus, thelonger-pitched thread portion 183 allows the user to quickly close theanvil 60 to the tissue in a tissue pre-compressing state. Thereafter, itis desirable to compress the tissue slowly so that the user has controlto avoid over-compression of the tissue. As such, the shorter pitchedthread portion 184 is used over this latter range of movement andprovides the user with a greater degree of control. During suchcompression, the force switch 400 seen in FIG. 18 and described inco-pending U.S. Patent Provisional Application Ser. No. 60/801,989 canbe used to indicate to the user through the tissue compression indicator14 (and/or to the control circuitry of the circuit board 500) that thetissue is being compressed with a force that is greater than thepre-load of the spring 420 inside the force switch 400. It is noted thatFIG. 18 illustrates the force switch 400 embodiment in the normally-openconfiguration described as the first exemplary embodiment of U.S. PatentProvisional Application Ser. No. 60/801,989. A strain gauge can also beused for measuring tissue compression.

FIGS. 19 to 23 illustrate movement of the rod 180 from an anvil-extendedposition (see FIGS. 19 to 20 ), to a 1-cm-closure-distance position (seeFIG. 21 ), to a staple-fire-ready position (see FIG. 22 ), and, finally,to an anvil fully closed position (see FIG. 23 ). Movement of the rod180 is controlled electrically (via the circuit board 500) by contactbetween a portion of a cam surface actuator 185 on the rod 180 andactuating levers or buttons of a series of micro-switches positioned inthe handle body 10.

A rod-fully-extended switch 610 (see FIG. 19 ) is positioned distal inthe handle body 10 to have the actuator 185 compress the activationlever of the rod-fully-extended switch 610 when the rod 180 (and,thereby, the anvil 60) is in the fully extended position. A 1-cm switch612 is positioned in an intermediate position within the handle body 10(see FIGS. 20 to 21 ) to prevent a 1-cm cam surface portion 186 of therod 180 from pressing the activation button of the 1-cm switch 612 whenthe rod 180 (and, thereby, the anvil 60) is within 1 cm of the fullyclosed position. After passing the 1-cm closure distance, as shown inFIG. 22 , the cam surface actuator 185 engages a staple-fire-readyswitch 614. The lower end of the actuator 185 as viewed in FIGS. 22 to23 has a bevel on both the forward and rear sides with respect to thebutton of the staple-fire-ready switch 614 and the distance between theportion on the two bevels that actuates the button (or, only the flatportion thereof) corresponds to the acceptable staple forming range(i.e., safe firing length) of the staples in the staple cartridge 50.Thus, when the button of the staple-fire-ready switch 614 is depressedfor the first time, the distance between the anvil 60 and the staplecartridge 50 is at the longest range for successfully firing and closingthe staples. While the button is depressed, the separation distance 62of the anvil 60 (see FIG. 18 ) remains within a safe staple-firingrange. However, when the button of the staple-fire-ready switch 614 isno longer depressed—because the actuator 185 is positioned proximally ofthe button, then staples will not fire because the distance is too shortfor therapeutic stapling. FIG. 23 show the rod 180 in the proximal-mostposition, which is indicated by the top end of the actuator 185 closingthe lever of a rod fully-retracted switch 616. When this switch 616 isactuated, the programming in the circuit board 500 prevents the motor120 from turning in a rod-retraction direction; in other words, it is astop switch for retracting the rod 180 in the proximal direction.

It is noted that FIGS. 2 to 3, 11 to 12, and 16 illustrate the distalend of the rod 180 not being connected to another device at its distalend (which would then contact the proximal end of the force switch 400).The connection band or bands between the distal end of the rod 180 andthe proximal end of the force switch 400 are not shown in the drawingsonly for clarity purposes. In an exemplary embodiment, the pull-bandsare flat and flexible to traverse the curved underside of the cartridgeplunger 320 through the anvil neck 30 and up to the proximal end of theforce switch 400. Of course, if the force switch 400 is not present, thebands would be connected to the proximal end of the trocar tip 410 thatreleasably connects to the proximal end of the anvil 60.

Functionality of the staple control assembly 200 is described withregard to FIGS. 12 to 16 and 24 to 27 , in particular, to FIG. 24 . Thestapling motor 210 is held between a motor bearing 222 and a motor shaftcover 224. The axle 212 of the stapling motor 210 is rotationallyconnected to the proximal end of the flexible coupling 240 and thedistal end of the flexible coupling 240 is rotationally connected to theproximal end of the screw 250, which rotates on bearings 260, 270, 280that are disposed within the intermediate coupling mount 230 and thedistal plate 232. The longitudinally translating nut 290 is threadedonto the screw 250 between the coupling mount 230 and the distal plate232. Therefore, rotation of the axle 212 translates into a correspondingrotation of the screw 250.

The nut coupling bracket 300 is longitudinally fixed to the nut 290 andto the stiffening rod 310 and the firing bracket 330. The firing bracket330 is longitudinally fixed to the cartridge plunger 320, which extends(through a non-illustrated staple driver) up to the staple cartridge 50(or to the staples). With such a connection, longitudinal movement ofthe nut 290 translates into a corresponding longitudinal movement of thecartridge plunger 320. Accordingly, when the staple firing switch 22 isactivated, the stapling motor 210 is caused to rotate a sufficientnumber of times so that the staples are completely fired from the staplecartridge 50 (and the cutting blade, if present, is extended tocompletely cut the tissue between the anvil 60 and the staple cartridge50). Programming in the circuitry, as described below, then causes thecartridge plunger 320 to retract after firing and remove any portion ofthe staple firing parts and/or the blade within the staple cartridge 50from the anvil-cartridge gap 62.

Control of this stapling movement, again, occurs through micro-switchesconnected to the circuit board 500 through electrical connections, suchas wires. A first of these control switches, the proximal staple switch618, controls retraction of the staple control assembly 200 and definesthe proximal-most position of this assembly 200. To actuate this switch,an actuation plate 306 is attached, in an adjustable manner, to a sideof the nut coupling bracket 300. See, e.g., FIGS. 6 and 24 . As such,when the nut 290 moves proximally to cause the plate 306 on the nutcoupling bracket 300 to activate the proximal staple switch 618, powerto the stapling motor 210 is removed to stop further proximally directedmovement of the staple control assembly 200.

A second of the switches for controlling movement of the staple controlassembly 200 is located opposite a distal transverse surface of thestiffening rod 310. See, e.g. FIG. 27 . At this surface is disposed alongitudinally adjustable cam member 312 that contacts a distal stapleswitch 620. In an exemplary embodiment, the cam member 312 is a screwthat is threaded into a distal bore of the stiffening rod 310.Accordingly, when the nut 290 moves distally to cause the cam member 312of the stiffening rod 310 to activate the distal staple switch 620,power to the stapling motor 210 is removed to stop further distallydirected movement of the staple control assembly 200.

FIGS. 28 and 29 illustrate a removable connection assembly to permitreplacement of a different staple cartridge 60 on the distal end of theanvil 30.

The proximal-most chamber of the handle body 10 defines a cavity forholding therein a power supply 600. This power supply 600 is connectedthrough the circuit board 500 to the motors 120, 210 and to the otherelectrical components of the stapler 1.

The electronic components of the stapler 1 have been described ingeneral with respect to control through the circuit board 500. Theelectric stapler 1 includes, as set forth above in an exemplaryembodiment, two drive motors 120, 210 powered by batteries andcontrolled through pushbuttons 20, 21, 22. The ranges of travel of eachmotor 120, 210 are controlled by limit switches 610, 616, 618, 620 atthe ends of travel and at intermediary locations 612, 614 along thetravel. The logic by which the motors 120, 210 are controlled can beaccomplished in several ways. For example, relay, or ladder logic, canbe used to define the control algorithm for the motors 120, 210 andswitches 610, 612, 614, 616, 618, 620. Such a configuration is a simplebut limited control method. A more flexible method employs amicroprocessor-based control system that senses switch inputs, locksswitches out, activates indicator lights, records data, provides audiblefeedback, drives a visual display, queries identification devices (e.g.,radio frequency identification devices (RFIDs) or cryptographicidentification devices), senses forces, communicates with externaldevices, monitors battery life, etc. The microprocessor can be part ofan integrated circuit constructed specifically for the purpose ofinterfacing with and controlling complex electro-mechanical systems.Examples of such chips include those offered by Atmel, such as the Mega128, and by PIC, such as the PIC 16F684.

A software program is required to provide control instructions to such aprocessor. Once fully developed, the program can be written to theprocessor and stored indefinitely. Such a system makes changes to thecontrol algorithm relatively simple; changes to the software that areuploaded to the processor adjust the control and user interface withoutchanging the wiring or mechanical layout of the device.

For a disposable device, a power-on event is a one time occurrence. Inthis case, the power-on can be accomplished by pulling a tab or arelease that is permanently removed from the device. The removal enablesbattery contact, thus powering on the device.

In any embodiment of the device, when the device is powered on, thecontrol program begins to execute and, prior to enabling the device foruse, goes through a routine that ensures awareness of actual positionsof the extend/retract and firing sub-assemblies, referred to as a homingroutine. The homing routine may be executed at the manufacturer prior toshipping to the user. In such a case, the homing routine is performed,the positions of the assemblies are set, and the device is shipped tothe user in a ready-to-use condition. Upon power-up, the device verifiesits positions and is ready to use.

Visual indicators (e.g., LEDs) are used to provide feedback to the user.In the case of the pushbutton switches 20, 21, 22, they can be lit (orbacklit) when active and unlit when not active. The indicators can blinkto convey additional information to the user. In the case of a delayedresponse after a button press, a given light can blink at anever-increasing rate as the response becomes imminent, for example. Theindicators can also light with different colors to indicate variousstates.

Cams are used in various locations at the stapler 1 to activate limitswitches that provide position information to the processor. By usinglinear cams of various lengths, position ranges can be set.Alternatively, encoders can be used instead of limit switches (absoluteand incremental positioning). Limit switches are binary: off or on.Instead of binary input for position information, encoders (such asoptical encoders) can be used to provide position information. Anotherway to provide position feedback includes mounting pulse generators onthe end of the motors that drive the sub-assemblies. By counting pulses,and by knowing the ratio of motor turns to linear travel, absoluteposition can be derived.

Use of a processor creates the ability to store data. For example,vital, pre-loaded information, such as the device serial number andsoftware revision can be stored. Memory can also be used to record datawhile the stapler 1 is in use. Every button press, every limit switchtransition, every aborted fire, every completed fire, etc., can bestored for later retrieval and diagnosis. Data can be retrieved througha programming port or wirelessly. In an exemplary embodiment, the devicecan be put into diagnostic mode through a series of button presses. Inthis diagnostic mode, a technician can query the stapler 1 for certaindata or to transmit/output certain data. Response from the stapler 1 tosuch a query can be in the form of blinking LEDs, or, in the case of adevice with a display, visual character data, or can be electronic data.As set forth above, a strain gauge can be used for analog output and toprovide an acceptable strain band. Alternatively, addition of a secondspring and support components can set this band mechanically.

An exemplary control algorithm for a single fire stapler 1 can includethe following steps:

-   -   Power on.    -   Verify home position and go to home position, if        necessary/desired.    -   Enable extend/retract buttons (lit) and disable (unlit) staple        fire button.    -   Enable staple fire button only after full extension (anvil        removal) and subsequent retraction with extend/retract buttons        remaining enabled.    -   Upon actuation of staple fire button, retract anvil until force        switch is activated.    -   Begin countdown by blinking fire button LED and increase blink        rate as firing cycle becomes imminent. Continue monitoring of        force switch and retract anvil so that force switch remains        activated.    -   During staple fire cycle, any button press aborts staple fire        routine.    -   If abort occurs before staple firing motor is activated, firing        cycle stops, anvil is extended to home position, and staple fire        button remains active and ready for a re-fire.    -   Alternatively, if the abort occurs during movement of firing        motor, firing cycle stops, firing motor is retracted, anvil is        returned to home position, and firing button is rendered        inactive. Accordingly, stapler (or that staple cartridge) cannot        be used.    -   After countdown to fire is complete, staple range limit switch        is queried for position. If staple range limit switch is        activated—meaning that anvil is within an acceptable staple        firing range—then staple firing motor is activated and firing        cycle proceeds. If staple range limit switch is not activated,        then firing cycle is aborted, anvil is returned to home        position, and staple firing button remains active ready for a        re-fire attempt.    -   After a completed staple firing, anvil remains in closed        position and only the extend button remains active. Once anvil        is extended to at least the home position, both extend and        retract buttons are made active. Staple fire button remains        inactive after a completed staple firing.        Throughout the above exemplary cycle, button presses, switch        positions, aborts, and/or fires can be recorded.

In a surgical procedure, the stapler is a one-way device. In the testmode, however, the test user needs to have the ability to move thetrocar 410 and anvil 60 back and forth as desired. The power-on featurepermits entry by the user into a manual mode for testing purposes. Thistest mode can be disengaged and the stapler reset to the use mode forpackaging and shipment.

For packaging, it is desirable (but not necessary) to have the anvil 60be disposed at a distance from the staple cartridge 50. Therefore, ahoming sequence can be programmed to place the anvil 60 one centimeter(for example) away from the staple cartridge 50 before powering down forpackaging and shipment.

When the electric stapler is unpackaged and ready to be used forsurgery, the user turns the stapler on (switch 12). Staples should notbe allowed to fire at any time prior to being in a proper staple-firingposition and a desired tissue compression state. Thus, the anvil/trocarextend/retract function is the only function that is enabled. In thisstate, the extend and retract buttons 20, 21 are lit and the staplefiring switch 22 is not lit (i.e., disabled).

Before use inside the patient, the trocar 410 is extended and the anvil60 is removed. If the stapler is being used to anastomose a colon, forexample, the trocar 410 is retracted back into the anvil neck 30 and thestaple cartridge 50 and anvil neck 30 are inserted trans-anally into thecolon to a downstream side of the dissection. The anvil 60, in contrast,is inserted through an upstream laparoscopic incision and placed at theupstream side of the dissection. The anvil 60 is attached to the trocar410 and the two parts are retracted towards the staple cartridge 50until a staple ready condition occurs. As set forth above, the anvil ismoved to a distance that does not substantially compress and,specifically, does not desiccate, the tissue therebetween. At thispoint, staple firing can occur when desired.

The staple firing sequence is started by activating the staple fireswitch 22. Staple firing can be aborted anytime during the firingsequence, whether prior to movement (during the blanching cycle) orduring movement (whether the staples have started to form or not). Thesoftware is programmed to begin a staple firing countdown sequencebecause it is understood that the tissue needs to be compressed andallowed to desiccate before staple firing should occur. Thus, after thestaple firing switch 22 is activated, the anvil 60 closes upon theinterposed tissue and begins to compress the tissue. The staple firingsequence includes an optimal tissue compression (OTC) measurement and afeedback control mechanism that causes staples to be fired only when thecompression is in a desired pressure range, referred to as the OTCrange, and a sufficient time period has elapsed to allow fluid removalfrom the compressed tissue. The OTC range is known beforehand based uponknown characteristics of the tissue that is to be compressed between theanvil 60 and the staple cartridge 50 (the force switch can be tuned fordifferent tissue OTC ranges). It is the force switch 400 that providesthe OTC measurement and supplies the microprocessor with informationindicating that the OTC for that particular tissue has been reached. TheOTC state can be indicated to the user with an LED, for example.

When the firing sequence begins, the staple fire switch 22 can be madeto blink at a given rate and then proceed to blink faster and faster,for example, until firing occurs. If no abort is triggered during thiswait time, the OTC state will remain for the preprogrammed desiccationduration and staple filing will occur after the countdown concludes. Inthe example of colon anastomosis with a circular stapler, stapling ofthe dissection occurs simultaneously with a cutting of tissue at thecenter of the dissection. This cutting guarantees a clear opening in themiddle of the circular ring of staples sufficient to create an openingfor normal colon behavior after the surgery is concluded.

As the liquid from the interposed compressed tissue is removed, thecompressive force on the tissue naturally reduces. In some instances,this reduction can be outside the OTC range. Therefore, the programincludes closed-loop anvil-compression control that is dependent uponcontinuous measurements provided by the force switch 400. With thisfeedback, the compressed tissue is kept within the OTC range throughoutthe procedure and even after being desiccated.

During the staple firing cycle, any actuation of a control switch by theuser can be programmed to abort the staple fire routine. If an abortoccurs before the staple firing motor 210 is activated, the firing cyclestops, the anvil 60 is extended to a home position, and the staple fireswitch 22 remains active and ready for a re-fire attempt, if desired.Alternatively, if the abort occurs during movement of the staple firingmotor 210, the firing cycle stops and the staple firing motor 210 iscaused to extend the anvil 60 to its home position. At this point, thestaple firing switch 22 is rendered inactive. Accordingly, the stapler(or that particular staple cartridge) can no longer be used (unless thestaple cartridge is replaced).

It is noted that before a staple firing can occur, a staple range limitswitch is queried for relative position of the staple cartridge 50 andanvil 60. If the staple range limit switch is activated—meaning thatanvil 60 is within an acceptable staple firing range—then the staplefiring motor 210 can be made active and the firing cycle can be allowedto proceed. If the staple range limit switch is not activated, then thefiring cycle is aborted, the anvil 60 is returned to the home position,and the staple firing switch 22 remains active and ready for a re-fireattempt.

Powering (also referred to as actuating, powering, controlling, oractivating) of the motor and/or the drive train of any portion of theend effector (e.g., anvil or stapler/cutter) is described herein. It isto be understood that such powering need not be limited to a singlepress of an actuation button by the user nor is the powering of a motorlimited to a single energizing of the motor by the power supply. Controlof any motor in the device can require the user to press an actuationbutton a number of times, for example, a first time to actuate a portionof the end effector for a first third of movement, a second time for asecond third of movement, and a third time for a last third of movement.More specifically for a surgical stapler, a first exemplary actuationcan move the staple sled or blade past the lock-out, a second exemplaryactuation can move the part up to the tissue, and a third exemplaryactuation can move the sled past all staples to the end of the staplecartridge. Similarly, powering of a motor need not be constant, forexample, where the motor is energized constantly from the time that theblade begins movement until it reaches the end point of its movement.Instead, the motor can be operated in a pulsed mode, a first example ofwhich includes periodically switching on and off the power supplied bythe power supply to the motor during actuation of an end effectorfunction. More specifically for a stapler, the motor can be pulsed tentimes/second as the staple/cutter moves from its proximal/start positionto its distal-most position. This pulsing can be directly controlled orcontrolled by microprocessor, either of which can have an adjustablepulse rate. Alternatively, or additionally, the motor can be operatedwith a pulse modulation (pulse-width or pulse-frequency), with pulsesoccurring at very short time periods (e.g., tenths, hundredths,thousandths, or millionths of a second). Accordingly, when the powersupply, the motor, and/or the drive train are described herein as beingpowered, any of these and other possible modes of operation areenvisioned and included.

After a completed staple firing, the anvil 60 remains in the closedposition and only the extend switch 20 remains active (all otherswitches are deactivated). Once the anvil 60 is extended to at least thehome position, both the extend and retract switches 20, 21 are madeactive but the retraction switch 21 does not permit closure of the anvil60 past the home position. The staple fire switch 22 remains inactiveafter a completed staple firing.

As set forth above, the anvil neck 30 houses a linear force switch 400connected to the trocar 410. This switch 400 is calibrated to activatewhen a given tensile load is applied. The given load is set tocorrespond to a desired pressure that is to be applied to the particulartissue before stapling can occur. Interfacing this switch 400 with theprocessor can ensure that the firing of staples only occurs within theOTC range.

The following text is an exemplary embodiment of a program listing forcarrying out the methods described herein. The text that follows is onlysubmitted as exemplary and those of skill in the art can appreciate thatprogramming the disclosed methods can take many different forms toachieve the same functionality.

'Circular Stapler Program using the rev 3c board (cb280 chipset) V8.03(CS-080306.CUL)

'8-3-06

'Modified program to abort with only fire button, added pbcount variable

'Added PWM ramping

'7-28-06

'final tweaks-stan is now an integer etc.

'7-17-06 This version written for the 3c board

'7-14 DEBUGGING VERSION

'Program written for 3c board using the Cubloc 280 chipset

'Debug “Fire aborted before firing!!”,Cr

Out 31,0 'turn retract motor off

Out 32,0 'turn fire forward off DDD

Out 23,0 'turn force led off

Pwm 1,fast,60000

Delay 250

Do Until Keyin(16,20)=0 'retract fire motor

Out 33,1

Loop

Out 33,0

Pwmoff 1

Out 22,0 'turn fire led off

Incr cycabortfires

If cycabortfires>=255 Then cycabortfires=255

Eewrite ds+1,cycabortfires,1 'write the current cycle abortfires to theeeprom

Delay 200

homeextend 'extend to 1 cm

End Sub

Also mentioned above is the possibility of using identification deviceswith removable and/or interchangeable portions of the end effector. Suchidentification devices, for example, can be used to track usage andinventory.

One exemplary identification device employs radio-frequency and isreferred to as an RFID. In an exemplary embodiment where a medicalstapler uses re-loadable, interchangeable staple cartridges, such as thestapler 1 described herein, an RFID can be placed in the staplecartridge to ensure compatibility with the particular stapler and anRFID reader for sensing compatible staple cartridges can be associatedwith the handle. In such a configuration, the reader interrogates theRFID mounted in the cartridge. The RFID responds with a unique code thatthe stapler verifies. If the stapler cartridge is labeled as verified,the stapler becomes active and ready for use. If the cartridge isrejected, however, the stapler gives a rejected indication (e.g., ablinking LED, an audible cue, a visual indicator). To avoid accidentalor improper reading of a nearby staple cartridge, the antenna of theRFID reader can be constructed to only read the RFID when the staplecartridge is installed in the stapler or is very nearby (optimally, atthe distal end of the device). Use of the RFID can be combined with amechanical lockout to ensure that only one fire cycle is allowed perstaple cartridge. RFIDs have drawbacks because the readers areexpensive, the antennas are required to be relatively large, and thedistance for reading is relatively close, typically measured incentimeters.

Other wireless authentication measures can be employed. Active RFIDs canbe used. Similarly, infrared (IR) transmission devices can be used.However, both of these require the generation of power at the receivingend, which is a cost and size disadvantage.

Another exemplary identification device employs encryption. Withencryption comes the need for processing numbers and, associated withsuch calculations, is use of processing chips (e.g., a microprocessor),one of which is to be placed on the interchangeable part, such as astaple cartridge or a replaceable end effector shaft. Such encryptionchips have certain characteristics that can be analyzed for optimizationwith the surgical instrument. First, a separate power source for theinterchangeable part is not desired. Not only would such a power sourceadd cost, it would also add undesirable weight and take up space that isneeded for other features or is just not available. Thus, power supplyto the part should come from the already existing power supply withinthe handle. Also, supply of power should be insured at all times.Because the interchangeable part is relatively small, the encryptionchip should be correspondingly small. Further, both the handle and theinterchangeable part are configured to be disposable, therefore, bothencryption processors should have a cost that allows disposability.Finally, connections between the encryption device on theinterchangeable part and the corresponding encryption device on thehandle should be minimized. As will be discussed below, the encryptiondevice provides all of these desirable characteristics and limits theundesirable ones.

Devices for encrypted identification are commercially available. One ofsuch encryption devices is produced by Dallas Semiconductor and isreferred to as the DS2432 chip. The DS2432 chip not only providesencrypted identification between a reader and a transponder, but it alsohas a memory that can be used to store device-specific information,which information and its uses will be described in further detailbelow. One beneficial characteristic of the DS2432 is that it is a1-wire device. This means that the power and both of the input andoutput signals travel on the same line. With a 1-wire device such as theDS2432, there is only the need for a single wire to traverse thedistance from the handle body 10 through the anvil neck 30 to theinterchangeable staple cartridge 50 in order to make a connectionbetween the handle and the end effector. This configuration satisfiesthe characteristic of having a minimal amount of electrical connectionsand has a correspondingly reduced cost for manufacture. It is true thatthe DS2432 chip requires ground, however, the metallic anvil neck 30 iselectrically conducting and is connected to ground of the device 1,therefore, an exemplary embodiment for the ground connection of theDS2432 chip is made by direct electrical contact through a lead to theneck 30 or by directly connecting the chip's ground to the neck 30.

One exemplary encryption circuit configuration places a first encryptionchip on the interchangeable part (e.g., the staple cartridge). Groundfor the first encryption chip is electrically connected to a metallicportion of the interchangeable part which, in turn, is electricallyconnected to ground of the device, for example, to the neck 30. The1-wire connection of the DS2432 chip is electrically connected to acontact pad that is somewhere on the interchangeable part but iselectrically disconnected from ground. For example, if theinterchangeable part is a linear 60 mm staple cartridge, the DS2432 canbe attached to or embedded within the electrically insulated distal endof the cartridge distal of the last staple set. The encryption chip canbe embedded on a side of the cartridge opposite the staple ejection faceso that it is neither exposed to the working surfaces nor to the exposedtissue when in use. The ground lead of the DS2432 chip can beelectrically connected to the metallic outer frame of the staplecartridge, which is electrically connected to ground of the stapler. The1-wire lead is electrically connected to a first conductive device (suchas a pad, a lead, or a boss) that is electrically insulated from themetallic frame of the cartridge. A single electrically conductive butinsulated wire is connected at the proximal end to the circuit board orto the appropriate control electronics within the handle of the device.This wire is insulated from electrical contact with any other part ofthe stapler, especially the grounded frame, and travels from the handle,through the neck and up to the receiving chamber for the interchangeablepart. At the distal end, the insulated wire is exposed and electricallyconnected to a second conductive device (such as a pad, a lead, or aboss) that is shaped to positively contact the first conductive deviceon the cartridge when the cartridge is locked into place in the endeffector. In such a configuration, the two conductive devices form adirect electrical connection every time that the interchangeable part(e.g., the staple cartridge) is inserted within the end effector; in oneparticular embodiment, contact can be made only when the part iscorrectly inserted.

The DS2432 is also only a few square millimeters in area, making thechip easy to install on a small interchangeable part, such as a staplecartridge, while simultaneously satisfying the minimal size requirement.It is noted that the DS2432 chip is relatively inexpensive. To keep allcommunication with the DS2432 chip hidden from outside examination, aDS2460 (also manufactured by Dallas Semiconductor) can be used toperform a comparison of an encrypted transmission received from a DS2432with an expected result calculated internally. The characteristics ofboth of these chips are explained, for example, by DallasSemiconductors' Application Note 3675, which is hereby incorporated byreference herein in its entirety. The DS2460 chip costs significantlymore than the DS2432 chip, but is still inexpensive enough to bedisposed along with the handle. It is noted that the number ofdisposable interchangeable parts of medical devices (such as thesurgical instrument disclosed herein) typically outnumber the handlethat receives the interchangeable parts by a significant amount.Accordingly, if the DS2432 chip is placed in the interchangeable partand the DS2460 chip is placed in the handle, the low cost encryptioncharacteristic is satisfied. There exists an alternative circuitconfiguration using two DS2432 chips that is explained in FIG. 2 ofApplication Note 3675, which circuit eliminates the need of the moreexpensive DS2460 chip by performing the comparison with a localmicroprocessor (e.g., microprocessor 2000). In such a configuration, thecost for adding encryption into the device 1 is reduced, however, asexplained, the configuration gives up some aspects of security by makingavailable to inspection both numbers that are to be compared.

The process for electronically verifying the identity of aninterchangeable part on a medical device using encryption is describedwith an exemplary embodiment having one DS2432 chip and one DS2460 chip.The exemplary control circuit for the encryption device is shown in FIG.30 . This exemplary embodiment is described using a linear staplerhaving a handle containing therein a circuit board with a microprocessor2000. One free I/O pin 2010 of the microprocessor 2000 is connected to afirst lead 2110 of the DS2460 and another I/O pin 2020 is connected to asecond lead 2120. Each interchangeable part 2200 is provided with aDS2432 chip and the 1-wire lead is connected to a third I/O pin 2030 ofthe microprocessor 2000.

To start the process, an interchangeable part 2200 is connected to thedevice, making electrical contact with ground and with the 1-wire lead.When the microprocessor 2000 detects that a new part 2200 has beenconnected to the device 1, it runs an authentication routine. First, themicroprocessor 2000 initiates a random number request to the DS2460 overthe first communication pin 2010. The DS2460 has a pre-programmed secretnumber that is the same as the pre-programmed secret numbers stored ineach of the DS2432 chips contained on the interchangeable parts 2200.Therefore, when the same random number is provided to both the DS2432and the DS2460 chips, the output result from each of the two chips willbe identical. The DS2460 generates a random number and supplies it, viathe second pin 2020, to the microprocessor 2000 for forwarding, via pin2030, on to the DS2432 over the 1-wire lead. When the DS2432 receivesthe random number, it applies its SHA-1 algorithm (developed by theNational Institute of Standards and Technology (NIST)) tocryptographically generate a hash code reply. This hash code reply istransmitted back over the 1-wire lead to the microprocessor 2000 and isforwarded, via either pin 2010 or 2020 to the DS2460. During this periodof time, the DS2460 is also calculating its own a hash code reply.First, the DS2460 internally applies the same random number sent to theDS2432 to its own SHA-1 algorithm and stores, internally, the generatedhash code reply. The DS2460 also stores the hash code reply transmittedfrom the DS2432 through the microprocessor 2000. Both of the hash codereplies are compared and, if they are identical, the interchangeablepart 2200 is confirmed as authenticated. If there is a differencebetween the hash code replies, then the part 2200 is rejected and thedevice is placed in a state where the part 2200 either cannot be used orcan be used, but only after certain safeguards are met. For example,data regarding the time, date, environment, etc. and characteristics ofthe unauthenticated part can be stored for later or simultaneoustransmission to the manufacturer (or its agent) to inform themanufacturer that the user is attempting to use or has used anunauthorized part 2200 with the device. If there was no encryption inthe messages, the authentication messages could be intercepted andcounterfeit, pirated, or unauthorized parts 2200 could be used withouthaving to purchase the parts 2200 from an authorized distributor. In theexemplary encryption embodiment described herein, the only informationthat is transmitted across lines that can be examined is a single randomnumber and a single hash code reply. It is understood that it would takehundreds of years to decrypt this SHA-1-generated reply, thus reducingany incentive for reverse engineering.

Because the chips used in this example each have secure memories thatcan only be accessed after authentication occurs, they can be programmedto employ multiple secret keys each stored within the memory. Forexample, if the DS2460, has multiple keys stored therein and the parts2200 each have only one key selected from this stored set of multiplekeys, the DS2460 can act as a “master” key to the “general” single keysof the parts 2200.

By authenticating the interchangeable part of the surgical instrument,many positive results are obtained. First, the instrument manufacturercan prevent a user from using unauthorized parts, thereby insuring useof only authorized parts. Not only does this guarantee that themanufacturer can receive royalties from sales of the interchangeablepart, but it also allows the manufacture to insure that the quality ofthe surgical parts remains high. Having the encryption circuitry containmemory dramatically enhances the benefits provided by the systems,apparatuses, and methods disclosed herein. For example, if a single endeffector of a linear stapler can receive 30 mm, 60 mm, and 120 mm staplecartridges, for example, each size of the cartridges could be providedwith an individualized key and the handle can be programmed to store anduse each of these three keys. Upon receiving a hash code reply thatcorresponds to one, but not the other two internally calculated hashcode replies, the handle would know what kind of cartridge has beeninserted in the device. Each cartridge could also contain in its memorycartridge-specific parameters, such as staple sled movement length, thatare different among the various sized cartridges and, therefore, causethe handle to behave differently dependent upon the cartridge detected.The parameters examined can also account for revision levels in theparticular part. For example, a revision 1 cartridge could have certainparameters for use and, by detecting that particular cartridge,programming could cause the handle to not allow use of revision 1cartridges but allow use of revision 2 cartridges, or vice-versa.

Having memory on the encryption chips can also allow the cartridge tokeep track of other kinds of data. For example, the cartridge can storethe identity of each handle to which it was connected, the identity ofthe handle that fired the cartridge, the time, date and other temporaldata when use and/or connection occurred, how long it took to fire thecartridge, how many times the firing trigger was actuated during staplefiring, and many other similar parameters. One parameter in particularcould record data when the cartridge misfires. This would allow themanufacturer to determine if the cartridge was faulty or if user-erroroccurred, for example, the latter being investigated to assist the userwith remedial measures or other training. By having memory available atthe handle, other handle-relevant parameters could be stored, forexample, duration of each procedure, speed of each staple firing, torquegenerated at each firing, and/or load experienced throughout eachfiring. The memory could be powered for years merely from thelithium-based power cells already present in the handle. Thus, longevityof handle data can be ensured. The memory can be used to store all usesof a particular handle, along with relevant calendar data. For example,if a handle is only certified for use in a single surgical procedure butthe handle has data indicating that staple cartridges were fired days orweeks apart, then, when it was finally returned to the manufacturer forrecycling, the manufacturer could detect that the user (hospital,doctor, clinic, etc.) was improperly and, possibly, unsafely, using thehandle. Encrypted authentication can be used with removable batterypacks as well. Moreover, sensors can be added to any portion of thedevice for communicating information to be stored within the memory ofthe encryption chips. For example, temperature sensors can transmitoperating room temperature existing when the cartridge was fired. Thistemperature reading can be used to determine if later infection wascaused by improper temperature control existing during the procedure(e.g., in countries where air-conditioning is not available).

In the unlikely event that the stapler becomes inoperable during use, amechanical override or bail-out is provided to allow manual removal ofthe device from the patient. All bailout uses can be recorded with thememory existing on these encryption chips. Furthermore, data that couldindicate why bailout was necessary could be stored for laterexamination. For quality assurance, when bailout is detected, the handlecan be programmed to indicate that a certified letter should be sent tothe customer/user informing them of the bailout use.

As described above, the systems, apparatuses, and methods disclosedherein are not limited to a circular stapler, which has been used as anexemplary embodiment above, and can be applied to any surgical staplinghead, such as a linear stapling device, for example. Accordingly, alinear stapler is being used in the text that follows for variousexemplary embodiment. However, use of a linear stapler in this contextshould not be considered as limited only thereto.

Described above are components that exist along the staple control axis80 of linear and circular staplers and these components form the staplecontrol assembly 200. As set forth therein, the required force forproper staple ejection and tissue cutting can be over 200 pounds and,possibly, up to 250 pounds. It has been determined that minimumrequirements for carrying out the desired stapling and cutting functionswith a linear electric surgical stapler for human tissue (such as colontissue, for example) are:

-   -   1) delivering approximately 54.5 kg (120 pounds) of force over a        stroke of about 60 mm (˜2.4″) in approximately 3 seconds; or    -   2) delivering approximately 82 kg (180 pounds) of force over a        stroke of about 60 mm (˜2.4″) in approximately 8 seconds.        The electric-powered, hand-held linear surgical stapling device        disclosed herein can meet these requirements because it is        optimized in a novel way as set forth below.

To generate the force necessary to meet the above-mentionedrequirements, the maximum power (in watts) of the mechanical assemblyneeds to be calculated based upon the maximum limits of theserequirements: 82 kg over 60 mm in 3 seconds. Mathematical conversion ofthese figures generates an approximate maximum of 16 Watts of mechanicalpower needed at the output of the drive train. Conversion of theelectrical power into mechanical power is not 1:1 because the motor hasless than 100% efficiency and because the drive train also has less than100% efficiency. The product of these two efficiency ratings forms theoverall efficiency. The electrical power required to produce the 16Watts of mechanical power is greater than the 16 Watts by an inverseproduct of the overall efficiency. Once the required electrical powercan be determined, an examination of available power supplies can bemade to meet the minimum power requirements. Thereafter, an examinationand optimization of the different power supplies can be made. Thisanalysis is described in detail in the following text.

Matching or optimizing the power source and the motor involves lookinginto the individual characteristics of both. When examining thecharacteristics of an electric motor, larger motors can perform a givenamount work with greater efficiency than smaller motors. Also motorswith rare-earth magnets or with coreless construction can deliver thesame power in a smaller size, but at higher cost. Further, in general,larger motors cost less than smaller motors if both are designed todeliver the same power over a given period of time. Larger motors,however, have an undesirable characteristic when used in surgicalstapling devices because the handle in which they are to be placed islimited by the size of an operator's hand. Physicians desire to usedevices that are smaller and lighter, not larger and heavier. Based uponthese considerations, cost, size, and weight are factors that can beoptimized for use in the surgical stapler handle.

Available motors for use within a physician's hand include motors withrelatively inexpensive ceramic magnets and motors with relativelyexpensive rare earth (i.e., neodymium) magnets. However, the powerincrease of the latter as compared to the former is not sufficientlylarge to warrant the substantial increase in cost of the latter. Thus,ceramic magnet motors can be selected for use in the handle. Exemplarymotors come in standard sizes (diameter) of 27.5 mm or 24 mm, forexample. These motors have a rated efficiency of approximately 60%(which decreases to 30% or below depending upon the size of the load).Such motors operate at speeds of approximately 30,000 rpm (between20,000 and 40,000 rpm) when unloaded.

Even though such conventional motors could be used, it would bedesirable to reduce the size even further. To that effect, the inventorshave discovered that coreless, brush-type, DC motors produce similarpower output but with a significant reduction in size. For example, a 17mm diameter coreless motor can output approximately the same power as astandard 24 mm diameter motor. Unlike a standard motor, the corelessmotor can have an efficiency of up to 80%. Coreless motors almost alluse rare earth magnets.

With such a limited volume and mechanical power available, it isdesirable to select a mechanical gear train having the greatestefficiency. Placing a rack and pinion assembly as the final drive traincontrol stage places a high-efficiency end stage in the drive train ascompared to a screw drive because, in general, the rack and pinion hasan approximate 95% efficiency, and the screw drive has a maximum ofabout 80% efficiency. For the linear electric stapler, there is a 60 mmtravel range for the stapling/cutting mechanism when the stapler has a60 mm cartridge (cartridges ranging from 30 mm to 100 mm can be used but60 mm is used in this example for illustrative purposes). With thistravel range, a 3-second, full travel duration places the rack andpinion extension rate at 0.8 inches per second. To accomplish this witha reasonably sized rack and pinion assembly, a gear train should reducethe motor output to approximately 60 rpm. With a motor output speed ofapproximately 30,000 rpm, the reduction in speed for the drive trainbecomes approximately 500:1. To achieve this reduction with the motor, a5-stage drive train is selected. It is known that such drive trains havean approximate 97% efficiency for each stage. Thus, combined with anapproximate 95% efficiency of the rack and pinion, the overallefficiency of the drive train is (0.95)(0.97)⁵ or 82%. Combining the 60%motor efficiency with the 82% drive train efficiency yields an overallelectrical to final mechanical efficiency of approximately 49.2%.Knowing this overall efficiency rating, when determining the amount ofelectrical power required for operating the stapler within the desiredrequirements, the actual electrical power needed is almost twice thevalue that is calculated for producing the stapling/cutting force.

To generate the force necessary to meet the above-mentionedrequirements, the power (in watts) of the mechanical assembly can becalculated based upon the 82 kg over 60 mm in 3 seconds to beapproximately 16 Watts. It is known that the overall mechanicalefficiency is 49.2%, so 32.5 Watts is needed from the power supply (16mech. watts≈32.5 elec. Watts×0.492 overall efficiency.). With thisminimum requirement for electrical power, the kind of cells available topower the stapler can be identified, which, in this case, includehigh-power Lithium Primary cells. A known characteristic of high-powerLithium cells (e.g., CR123 or CR2 cells) is that they produce about 5peak watts of power per cell. Thus, at least six cells in series willgenerate the required approximate amount of 32.5 watts of electricalpower, which translates into 16 watts of mechanical power. This does notend the optimization process because each type of high-power Lithiumcell manufactured has different characteristics for delivering peakpower and these characteristics differ for the load that is to beapplied.

Various battery characteristics exist that differentiate one battery ofa first manufacturer from another battery of a second manufacturer.Significant battery characteristics to compare are those that limit thepower that can be obtained from a battery, a few of which include:

-   -   type of electrolyte in the cell;    -   electrolyte concentration and chemistry;    -   how the anode and cathode are manufactured (both in chemistry        and in mechanical construction); and    -   type and construction of the PTC (positive temperature        coefficient of resistance) device.        Testing of one or more of these characteristics gives valuable        information in the selection of the most desirable battery for        use in the stapling device. It has been found that an        examination of the last characteristic—PTC device        behavior—allows an optimization of the type of battery to        perform the desired work.

Most power sources are required to perform, with relative certainty andefficiency, many times throughout a long period of time. When designingand constructing a power source, it is not typical to select the powersource for short-duration use combined with a low number of uses.However, the power source of an electric stapling device is only usedfor a short duration and for a small number of times. In each use, themotor needs to be ready for a peak load and needs to perform withouterror. This means that, for surgical staplers, the stapling/cuttingfeature will be carried out during only one medical procedure, which hascycle counts of between 10 and 20 uses at most, with each use needing toaddress a possible peak load of the device. After the one procedure, thedevice is taken out of commission and discarded. Therefore, the powersource needs to be constructed unlike any other traditional powersupply.

The device according to the systems, apparatuses, and methods disclosedherein are constructed to have a limited useful life of a power cell ascompared to an expected useful life of the power cell when not used inthe device. When so configured, the device is intended to work few timesafter this defined “life span.” It is known that self-contained powersupplies, such as batteries, have the ability to recover after some kindof use. For optimization, the device is constructed within certainparameters that, for a defined procedure, will perform accordingly butwill be limited or unable to continue performance if the time of useextends past the procedure. Even though the device might recover andpossibly be used again in a different procedure, the device is designedto use the power cells such that they will most likely not be able toperform at the enhanced level much outside the range of intended singleuse periods or outside the range of aggregate use time. With this inmind, a useful life or clinical life of the power supply or of thedevice is defined, which life can also be described as an intended use.It is understood that this useful/clinical life does not include periodsor occurrences of use during a testing period thereof to make sure thatthe device works as intended. The life also does not include other timesthat the device is activated outside the intended procedure, i.e., whenit is not activated in accordance with a surgical procedure.

Conventional batteries available in the market are designed to be usedin two ways: (1) provide a significant amount of power for a shortduration (such as in a high-drain digital device like cameras) or (2)provide a small amount of power over a long duration (such as acomputer's clock backup). If either of these operations is not followed,then the battery begins to heat up. If left unchecked, the battery couldheat to a point where the chemicals could cause significant damage, suchas an explosion. As is apparent, battery explosion is to be avoided.These extremes are prevented in conventional batteries with the presenceof the PTC device—a device that is constructed to limit conduction ofthe battery as the battery increases in temperature (i.e., a positivetemperature coefficient of resistance). The PTC device protectsbatteries and/or circuits from overcurrent and overtemperatureconditions. Significantly, the PTC device protects a battery fromexternal short circuits while still allowing the battery to continuefunctioning after the short circuit is removed. Some batteries provideshort-circuit and/or overtemperature protection using a one-time fuse.However, an accidental short-circuit of such a fused battery causes thefuse to open, rendering the battery useless. PTC-protected batterieshave an advantage over fused batteries because they are able toautomatically “reset” when the short circuit is removed, allowing thebattery to resume its normal operation. Understanding characteristics ofthe PTC device is particularly important because the motor will bedrawing several times greater current than would ever be seen in atypical high-drain application.

The PTC device is provided in series with the anode and cathode and ismade of a partially conducting layer sandwiched between two conductivelayers, for example. The device is in a low-resistance condition at atemperature during a normal operation (depending on circuit conditionsin which the device is used, for example, from room temperature to 40°C.). On exposure to high temperature due to, for example, unusuallylarge current resulting from the formation of a short circuit orexcessive discharge (depending on circuit conditions in which the deviceis used, for example, from 60° to 130° C.), the PTC device switches intoan extremely high-resistance mode. Simply put, when a PTC device isincluded in a circuit and an abnormal current passes through thecircuit, the device enters the higher temperature condition and,thereby, switches into the higher resistance condition to decrease thecurrent passing through the circuit to a minimal level and, thus,protect electric elements of the circuit and the battery/ies. At theminimal level (e.g., about 20% of peak current), the battery can cooloff to a “safe” level at which time greater power can be supplied. Thepartially conducting layer of the PTC device is, for example, acomposite of carbon powder and polyolefin plastic. Further descriptionof such devices is unnecessary, as these devices are described and arewell known in the art.

Because PTC circuits of different manufacturers operate with differentcharacteristic behaviors, the systems, apparatuses, and methodsdisclosed herein take advantage of this feature and provide a processfor optimizing the selection of a particular battery to match aparticular motor and a particular use. An examination of the time whenthe PTC device switches to the higher resistance condition can be usedas this indicator for optimizing a particular motor and drive train to abattery. It is desirable to know when the PTC device makes this switchso that, during normal stapler use, the PTC device does not make thischange.

Exemplary batteries were loaded with various levels from approximately 3amps to approximately 8 amps. At the high end, the PTC device changed tothe high-resistance state almost immediately, making this current leveltoo high for standard CR123 cells. It was determined that, for between 4and 6 amps, one manufacturer's cell had PTC activation sooner thananother manufacturer's cell. The longest PTC changeover duration for thesecond manufacturer was >3 minutes for 4 amps, approximately 2 minutesfor 5 amps, and almost 50 seconds for 6 amps. Each of these durationswas significantly greater than the 8-second peak load requirement.Accordingly, it was determined that the second manufacturer's cellswould be optimal for use at peak amps as compared to the firstmanufacturer's cells.

Initially, it was surmised that higher amperes with lower or constantvoltage would generate higher power out of the power cell(s). Based uponthe configuration of 6 cells in series, the peak voltage could be 18volts with a peak current of only 6 amps. Placing cells in parallel, intheory, should allow a higher peak amperage and a 3×2 configuration (twoparallel set of three cells in series) could have a 9 volt peak with upto a 12 amp peak.

Different single cells were investigated and it was confirmed that arelatively low voltage (about 1.5 to 2 volts) and approximately 4 to 6amperes produces the highest power in Watts. Two six-cell configurationswere examined: a 6×1 series connection and a 3×2 parallel connection.The 3×2 configuration produced the greatest peak amperes ofapproximately 10 amps. The 6×1 configuration produced about 6 amps peakand the single cell was able to peak at 5-6 amps before the PTC devicechanged state. This information indicated the state at which any singlecell in the series group would be activating its PTC device and, thus,limiting current through the entire group of cells. Thus, the tentativeconclusion of yielding peak amps at lower voltage with a 3×2configuration was maintained.

Three different CR123 battery configurations were tested: 4×1, 6×1, and3×2, to see how fast the pinion would move the rack (in inches persecond (“IPS”)) for the 120# and 180# loads and for a given typicalgearing. The results of this real world dynamic loading test are shownin the chart of FIG. 31 , for both the 120# load:

-   -   the 4×1 battery pack was able to move the load at about 0.6 IPS        at approximately 2.5 amps but at approximately 8 volts;    -   the 6×1 battery pack was able to move the load at about 0.9 IPS        at approximately 2.5 amps but at approximately 13 volts; and    -   the 3×2 battery pack was able to move the load at about 0.4 IPS        at approximately 2.5 amps but at approximately 6 volts;        and the 180# load:    -   the 4×1 battery pack was able to move the load at about 0.65 IPS        at approximately 4 amps but at approximately 7.5 volts;    -   the 6×1 battery pack was able to move the load at about 0.9 IPS        at approximately 4 amps but at approximately 12 volts; and    -   the 3×2 battery pack was able to move the load at about 0.4 IPS        at approximately 4 amps but at approximately 7 volts.

Clearly, the peak current was limited and this limit was dependent uponthe load. This experiment revealed that the motor drew a similar currentregardless of the power supply for a given load but that the voltagechanged depending upon the battery cell configuration. With respect toeither load, the power output was the greatest in the 6×1 configurationand not in the 3×2 configuration, as was expected. From this, it wasdetermined that the total power of the cell pack is driven by voltageand not by current and, therefore, the parallel configuration (3×2) wasnot the path to take in optimizing the power source.

Traditionally, when designing specifications for a motor, the windingsof the motor are matched to the anticipated voltage at which the motorwill be run. This matching takes into account the duration of individualcycles and the desired overall life of the product. In a case of anelectric stapling device the motor will only be used for very shortcycles and for a very short life, traditional matching methods yieldresults that are below optimal. Manufacturers of the motors give avoltage rating on a motor that corresponds to the number of turns of thewindings. The lower the number of turns, the lower the rated voltage.Within a given size of motor winding, a lower number of turns allowslarger wire to be used, such that a lower number of turns results in alower resistance in the windings, and a higher number of turns resultsin a higher resistance. These characteristics limit the maximum currentthat the motor will draw, which is what creates most of the heat anddamage when the motor is overdriven. For the systems, apparatuses, andmethods disclosed herein, a desirable configuration will have the lowestwinding resistance to draw the most current from the power supply (i.e.,battery pack). By running the motor at a voltage much higher than themotor rating, significantly greater power can be drawn from similarlysized motors. This trait was verified with testing of nearly identicalcoreless motors that only varied in winding resistance (and, hence, thenumber of turns). For example, 12-volt and 6-volt rated motors were runwith 6 cells (i.e., at 19.2 volts). The motors rated for 12 volts outputpeak power of 4 Watts with the battery voltage only falling slightly to18 volts when drawing 0.7 amps. In comparison, the motors rated for 6volts output 15 Watts of power with the voltage dropping to 15 volts butdrawing 2 amps of current. Therefore, the lower resistance windings wereselected to draw enough power out of the batteries. It is noted that themotor windings should be balanced to the particular battery pack sothat, in a stall condition, the motor does not draw current from thecells sufficient to activate the PTC, which condition wouldimpermissibly delay use of an electric surgical stapler during anoperation.

The 6×1 power cell configuration appeared to be more than sufficient tomeet the requirements of the electric stapling device. Nonetheless, atthis point, the power cell can be further optimized to determine if sixcells are necessary to perform the required work. Four cells were, then,tested and it was determined that, under the 120# load, the motor/drivetrain could not move the rack over the 60 mm span within 3 seconds. Sixcells were tested and it was determined that, under the 120# load, themotor/drive train could move the rack over the 60 mm span in 2.1seconds—much faster than the 3-second requirement. It was furtherdetermined that, under the 180# load, the motor/drive train could movethe rack over the 60 mm span in less than 2.5 seconds—much quicker thanthe 8-second requirement. At this point, it is desirable to optimize thepower source and mechanical layout to make sure that there is no“runaway” stapling/cutting; in other words, if the load is significantlyless than the required 180# maximum, or even the 120# maximum, then itwould not be desirable to have the rack move too fast.

The gear reduction ratio and the drive system need to be optimized tokeep the motor near peak efficiency during the firing stroke. Thedesired stroke of 60 mm in 3 seconds means a minimum rack velocity of 20mm/sec (˜0.8 inches/second). To reduce the number of variables in theoptimization process, a basic reduction of 333:1 is set in the gear box.This leaves the final reduction to be performed by the gears presentbetween the output shaft 214 of the gear box and the rack 217, whichgears include, for example, a bevel gear 215 and the pinion 216 (whichdrives the rack), a simplified example of which is illustrated in FIG.32 .

These variables can be combined into the number of inches of rack travelwith a single revolution of the output shaft 214 of the 333:1 gearbox.If the gearbox output (in rpm) never changed, it would be a simplefunction to match the inches of rack travel per output shaft revolution(“IPR”) to the output rpm to get a desired velocity as follows:(60 rpm→1 revolution/second (rps); 1 rps@0.8 IPR →0.8 in/sec).In such an idealized case, if the IPR is plotted against velocity, astraight line would be produced. Velocity over a fixed distance can befurther reduced to Firing Time. Thus, a plot of Firing Time versus IPRwould also be a straight line in this idealized case. However, output ofthe motor (in rpm) and, therefore, of the gearbox, is not fixed becausethis speed varies with the load. The degree of load determines theamount of power the motor can put out. As the load increases, the rpmsdecrease and the efficiency changes. Based upon an examination ofefficiency with differing loads, it has been determined that efficiencypeaks at just over 60%. However, the corresponding voltage and amperesat this efficiency peak are not the same as at the point of peak power.Power continues to increase as the load increases until the efficiencyis falling faster than the power is increasing. As the IPR increases, anincrease in velocity is expected, but a corresponding increase in IPRlowers the mechanical advantage and, therefore, increases the load. Thisincreasing load, with the corresponding decrease in efficiency atprogressively higher loads, means that a point will exist when greatervelocity out of the rack is no longer possible with greater IPR. Thisbehavior is reflected as a deviation from a predicted straight line inthe plot of Firing Time (in sec) versus IPR. Experimentation of thesystem disclosed herein reveals that the boundary between unnecessarymechanical advantage and insufficient mechanical advantage occurs atapproximately 0.4 IPR.

From this IPR value, it is possible to, now, select the final gear ratioof the bevel gear 215 to be approximately three times greater (3:1) thanthe sprocket of the output shaft. This ratio translates into anapproximate IPR of 0.4.

Now that the bevel gear 215 has been optimized, the battery pack can bereexamined to determine if six cells could be reduced to five or evenfour cells, which would save cost and considerably decrease the volumeneeded for the power supply within the handle. A constant load ofapproximately 120# was used with the optimized motor, drive train, bevelgear, and rack and pinion and it was discovered that use of 4 cellsresulted in an almost 5 second time period for moving the rack 60 mm.With 5 cells, the time was reduced to approximately 3.5 seconds. With a6-cell configuration, the time was 2.5 seconds. Thus, interpolating thiscurve resulted in a minimum cell configuration of 5.5 cells. Due to thefact that cells only can be supplied in integer amounts, it wasdiscovered that the 6-cell configuration was needed to meet therequirements provided for the electric stapling device.

From this, the minimum power source volume could be calculated as afixed value, unless different sized cells could be used that providedthe same electrical power characteristics. Lithium cells referred asCR2s have similar electrical power characteristics as have CR123s butare smaller. Therefore, using a 6-cell power supply of CR2s reduced thespace requirement by more than 17%.

As set forth in detail above, the power source (i.e., batteries), drivetrain, and motor are optimized for total efficiency to deliver thedesired output force within the required window of time for completingthe surgical procedure. The efficiency of each kind of power source,drive train, and motor was examined and, thereafter, the type of powersource, drive train, and motor was selected based upon this examinationto deliver the maximum power over the desired time period. In otherwords, the maximum-power condition (voltage and current) is examinedthat can exist for a given period of time without activating the PTC(e.g., approximately 15 seconds). The disclosed systems, apparatuses,and methods locate the voltage-current-power value that optimizes theway in which power is extracted from the cells to drive the motor. Evenafter such optimization, other changes can be made to improve upon thefeatures of the electric stapler 1.

Another kind of power supply can be used and is referred to herein as a“hybrid” cell. In such a configuration, a rechargeable Lithium-ion orLithium-polymer cell is connected to one or more of the optimized cellsmentioned above (or perhaps another primary cell of smaller size but ofa similar or higher voltage). In such a configuration, the Li-ion cellwould power the stapling/cutting motor because the total energycontained within one CR2 cell is sufficient to recharge the Li ion cellmany times, however, the primary cells are limited as to delivery.Li-ion and Li-Polymer cells have very low internal resistance and arecapable of very high currents over short durations. To harness thisbeneficial behavior, a primary cell (e.g., CR123, CR2, or another cell)could take 10 to 30 seconds to charge up the secondary cell, which wouldform an additional power source for the motor during firing. Analternative embodiment of the Li-ion cell is the use of a capacitor;however, capacitors are volume inefficient. Even so, a super capacitormay be put into the motor powering system; it may be disconnectedelectrically therefrom until the operator determines that additionalpower is required. At such a time, the operator would connect thecapacitor for an added “boost” of energy.

As mentioned above, if the load on the motor increases past a givenpoint, the efficiency begins to decrease. In such a situation, amulti-ratio transmission can be used to change the delivered power overthe desired time period. When the load becomes too great such thatefficiency decreases, a multi-ratio transmission can be used to switchthe gear ration to return the motor to the higher efficiency point, atwhich, for example, at least a 180# force can be supplied. It is noted,however, that the motor needs to operate in both forward and reversedirections. In the latter operating mode, the motor must be able todisengage the stapling/cutting instrument from out of a “jammed” tissueclamping situation. Thus, it would be beneficial for the reverse gearingto generate more force than the forward gearing.

With significantly varying loads, e.g., from low pounds up to 180pounds, there is the possibility of the drive assembly being toopowerful in the lower end of the load range. Thus, the systems,apparatuses, and methods disclosed herein can include a speed governingdevice. Possible governing devices include dissipative (active)governors and passive governors. One exemplary passive governor is aflywheel, such as the energy storage element 56, 456 disclosed in U.S.Patent Application No. 2005/0277955 to Palmer et al. Another passivegovernor that can be used is a “fly” paddlewheel. Such an assembly useswind resistance to govern speed because it absorbs more force as itspins faster and, therefore, provides a speed governing characteristicwhen the motor is moving too fast. Another kind of governor can be acompression spring that the motor compresses slowly to a compressedstate. When actuation is desired, the compressed spring is released,allowing all of the energy to be transferred to the drive in arelatively short amount of time. A further exemplary governor embodimentcan include a multi-stage switch having stages that are connectedrespectively to various sub-sets of the battery cells. When low force isdesired, a first switch or first part of a switch can be activated toplace only a few of the cells in the power supply circuit. As more poweris desired, the user (or an automated computing device) can placesuccessive additional cells into the power supply circuit. For example,in a 6-cell configuration, the first 4 cells can be connected to thepower supply circuit with a first position of a switch, the fifth cellcan be connected with a second position of the switch, and the sixthcell can be connected with a third position of the switch.

Electric motors and the associated gear box produce a certain amount ofnoise when used. The stapler disclosed herein isolates the motor and/orthe motor drive train from the handle to decrease both the acoustic andvibration characteristics and, thereby, the overall noise producedduring operation. In a first embodiment, a dampening material isdisposed between the handle body and both of motor and the drive train.The material can be foam, such as latex, polyester, plant-based,polyether, polyetherimide, polyimide, polyolefin, polypropylene,phenolic, polyisocyanates, polyurethane, silicone, vinyl, ethylenecopolymer, expanded polyethylene, fluoropolymer, or styrofoam. Thematerial can be an elastomer, such as silicone, polyurethane,chloroprene, butyl, polybutadiene, neoprene, natural rubber, orisoprene. The foam can be closed cellular, open cellular, flexible,reticular, or syntactic, for example. The material can be placed atgiven positions between the handle and motor/gear box or can entirelyfill the chamber surrounding the motor/gear box. In a second embodiment,the motor and drive train are isolated within a nested boxconfiguration, sometimes referred to as a “Chinese Box” or “Russiannesting doll.” In such a configuration, the dampening material is placedaround the motor/gear box and the two are placed within a first box withthe gear box shaft protruding therefrom. Then, the first box is mountedwithin the “second box”—the handle body—and the dampening material isplace between the first box and the handle interior.

The electric stapler disclosed herein can be used in surgicalapplications. Most stapling devices are one-time use. They can bedisposed after one medical procedure because the cost is relatively low.The electric surgical stapler, however, has a greater cost and it may bedesirable to use at least the handle for more than one medicalprocedure. Accordingly, sterilization of the handle components after usebecomes an issue. Sterilization before use is also significant. Becausethe electric stapler includes electronic components that typically donot go through standard sterilization processes (i.e., steam or gammaradiation), the stapler needs to be sterilized by other, possibly moreexpensive, means such as ethylene-oxide gas. It would be desirable,however, to make the stapler available to gamma radiation sterilizationto reduce the cost associated with gas sterilization. It is known thatelectronics are usable in space, which is an environment where suchelectronics are exposed to gamma radiation. In such applications,however, the electronics need to work while being exposed. In contrast,the electric stapler does not need to work while being exposed to thegamma sterilization radiation. When semiconductors are employed, even ifthe power to the electronics is turned off, gamma radiation willadversely affect the stored memory. These components only need towithstand such radiation and, only after exposure ceases, need to beready for use. Knowing this, there are various measures that can betaken to gamma-harden the electronic components within the handle.First, instead of use MOSFET memory, for example, fusable link memoriescan be used. For such memories, once the fuses are programmed (i.e.,burnt), the memory becomes permanent and resistant to the gammasterilization. Second, the memory can be mask-programmed. If the memoryis hard programmed using masks, gamma radiation at the level for medicalsterilization will not adversely affect the programming. Third, thesterilization can be performed while the volatile memory is empty and,after sterilization, the memory can be programmed through variousmeasures, for example, a wireless link including infrared, radio,ultrasound, or Bluetooth communication can be used. Alternatively, oradditionally, external electrodes can be contacted in a cleanenvironment and these conductors can program the memory. Finally, aradiopaque shield (made from molybdenum or tungsten, for example) can beprovided around the gamma radiation sensitive components to preventexposure of these components to the potentially damaging radiation.

As set forth herein, characteristics of the battery, drive train, andmotor are examined and optimized for an electric stapling application.The particular design (i.e., chemistry and PTC) of a battery willdetermine the amount of current that can be supplied and/or the amountof power that can be generated over a period of time. It has beendetermined that standard alkaline cells do not have the ability togenerate the high power needed over the short period of time to effectactuation of the electric stapling device. It was also determined thatsome lithium-manganese dioxide cells also were unable to meet the needsfor actuating the stapling device. Therefore, characteristics of certainlithium-manganese dioxide cell configurations were examined, such as theelectrolyte and the positive temperature coefficient device.

It is understood that conventional lithium-manganese dioxide cells(e.g., CR123 and CR2) are designed for loads over a long period of time.For example, SUREFIRE® markets flashlights and such cells and statesthat the cells will last for from 20 minutes to a few hours (3 to 6) atthe maximum lumen output of the flashlight. Load upon the cells(s)during this period of time is not close to the power capacity of thebattery(ies) and, therefore, the critical current rate of thebattery(ies) is not reached and there is no danger of overheating orexplosion. If such use is not continuous, the batteries can last throughmany cycles (i.e., hundreds) at this same full power output.

Simply put, such batteries are not designed for loads over a period of10 seconds or less, for example, five seconds, and are also not designedfor a small number of uses, for example, ten to fifteen. What thesystems, apparatuses, and methods disclosed herein do is to configurethe power supply, drive train, and motor to optimize the power supply(i.e., battery) for a small number of uses with each use occurring overa period of less than ten seconds and at a load that is significantlyhigher than rated.

All of the primary lithium cells that were examined possess a criticalcurrent rate defined by the respective PTC device and/or the chemistryand internal construction. If used above the critical current rate for aperiod of time, the cells can overheat and, possibly, explode. Whenexposed to a very high power demand (close to the PTC threshold) with alow number of cycles, the voltage and amperage profiles do not behavethe same as in prior art standard uses. It has been found that somecells have PTC devices that prevent generation of power required by thestapler of the systems, apparatuses, and methods disclosed herein, butthat other cells are able to generate the desired power (can supply thecurrent an voltage) for powering the electric stapling device. Thismeans that the critical current rate is different depending upon theparticular chemistry, construction, and/or PTC of the cell.

The systems, apparatuses, and methods disclosed herein configure thepower supply to operate in a range above the critical current rate,referred to herein as the “Super-Critical Current Rate.” It is notedwithin the definition of Super-Critical Current Rate also is anaveraging of a modulated current supplied by the power supply that isabove the critical current rate. Because the cells cannot last longwhile supplying power at the Super-Critical Current Rate, the timeperiod of their use is shortened. This shortened time period where thecells are able to operate at the Super-Critical Current Rate is referredto herein as the “Super-Critical Pulse Discharge Period,” whereas theentire time when the power supply is activated is referred to as a“Pulse Discharge Period.” In other words, the Super-Critical PulseDischarge Period is a time that is less than or equal to the PulseDischarge Period, during which time the current rate is greater than thecritical current rate of the cells. The Super-Critical Pulse DischargePeriod for the systems, apparatuses, and methods disclosed herein isless than about 16 seconds, in other words, in a range of about one-halfto fifteen seconds, for example, between two and four seconds and, moreparticularly, at about three seconds. During the life of the staplingdevice, the power supply may be subjected to the Super-Critical CurrentRate over the Pulse Discharge Period for at least one time and less thantwenty times within the time of a clinical procedure, for example,between approximately five and fifteen times, in particular, between tenand fifteen times within a period of five minutes. Therefore, incomparison to the hours of use for standard applications of the powersupply, the systems, apparatuses, and methods disclosed herein will havean aggregate use, referred to as the Aggregate Pulse Time, of, at most,approximately 200 to 300 seconds, in particular, approximately 225seconds. It is noted that, during an activation, the device may not berequired to exceed or to always exceed the Super-Critical Current Ratein a given procedure because the load presented to the instrument isdependent upon the specific clinical application (i.e., some tissue isdenser than others and increased tissue density will increase loadpresented to device). However, the stapler is designed to be able toexceed the Super-Critical Current Rate for a number of times during theintended use of the surgical procedure. Acting in this Super-CriticalPulse Discharge Period, the device can operate a sufficient amount oftimes to complete the desired surgical procedure, but not many morebecause the power supply is asked to perform at an increased current.

When performing in the increased range, the force generated by thedevice, e.g., the electric stapler 1, is significantly greater thanexisted in a hand-powered stapler. In fact, the force is so much greaterthat it could damage the stapler itself. In one exemplary use, the motorand drive assemblies can be operated to the detriment of the knife bladelock-out feature—the safety that prevents the knife blade 1060 fromadvancing when there is no staple cartridge or a previously fired staplecartridge in the staple cartridge holder 1030. This feature isillustrated in FIG. 33 . As discussed, the knife blade 1060 should beallowed to move distally only when the staple sled 102 is present at thefiring-ready position, i.e., when the sled 102 is in the positionillustrated in FIG. 33 . If the sled 102 is not present in thisposition, this can mean one of two things, either there is no staplecartridge in the holder 1030 or the sled 102 has already been moveddistally—in other words, a partial or full firing has already occurredwith the loaded staple cartridge. Thus, the blade 1060 should not beallowed to move, or should be restricted in its movement. Accordingly,to insure that the sled 102 can prop up the blade 1060 when in a firingstate, the sled 102 is provided with a lock-out contact surface 104 andthe blade 1060 is provided with a correspondingly shaped contact nose1069. It is noted at this point that, the lower guide wings 1065 do notrest against a floor 1034 in the cartridge holder 1030 until the blade1060 has moved distally past an edge 1035. With such a configuration, ifthe sled 102 is not present at the distal end of the blade 1060 to propup the nose 1069, then the lower guide wings 1065 will follow thedepression 1037 just proximal of the edge 1035 and, instead of advancingon the floor 1034, will hit the edge 1035 and prevent further forwardmovement of the blade 1060. To assist with such contact when the sled102 is not present (referred to as a “lock out”), the staple cartridge1030 has a plate spring 1090 (attached thereto by at least one rivet1036) for biasing the blade 1060. With the plate spring 1090 flexedupward and pressing downward against the flange 1067 (at least until theflange 1067 is distal of the distal end of the plate spring 1090), adownwardly directed force is imparted against the blade 1060 to pressthe wings 1065 down into the depression 1037. Thus, as the blade 1060advances distally without the sled 102 being present, the wings 1065follow the lower curve of the depression 1037 and are stopped fromfurther distal movement when the distal edge of the wings 1065 hit theedge 1035.

This safety feature operates as described so long as the forcetransmitted by the knife blades 1062 to the blade 1060 is not greatenough to tear off the lower guide wings 1065 from the blade 1060. Withthe forces able to be generated by the power supply, motor and drivetrain, the blade 1060 can be pushed distally so strongly that the wings1065 are torn away. If this occurs, there is no way to prevent distalmovement of the blade 1060 or the sled 102. Accordingly, the systems,apparatuses, and methods disclosed herein provide a way to lower theforces able to be imparted upon the wings 1065 prior to their passagepast the edge 1035. In other words, the upper limit of force able to beapplied to the blade 1060 is reduced in the first part of blade travel(past the edge 1035) and increases after the wings 1065 have cleared theedge 1035 and rest on the floor 1034. More specifically, a firstexemplary embodiment of this two-part force generation limiter takes theform of a circuit in which only one or a few of the cells in the powersupply are connected to the motor during the first part of thestapling/cutting stroke and, in the second part of the stapling/cuttingstroke, most or all of the cells in the power supply are connected tothe motor. A first exemplary form of such a circuit is illustrated inFIG. 34 . In this first embodiment, when the switch 1100 is in the “A”position, the motor (e.g., stapling motor 210) is only powered with onepower cell 602 (of a possible four in this exemplary embodiment).However, when the switch 1100 is in the “B” position, the motor ispowered with all four of the cells 602 of the power supply 600, therebyincreasing the amount of force that can be supplied to the blade 1060.Control of the switch 1100 between the A and B positions can occur bypositioning a second switch somewhere along the blade control assemblyor along the sled 102, the second switch sending a signal to acontroller after the wings 1065 have passed the edge 1035. It is notedthat this first embodiment of the control circuit is only exemplary andany similarly performing assembly can provide the lock-out protectionfor the device, see, for example, the second exemplary embodimentillustrated in FIG. 36 .

A first exemplary form of a forward and reverse motor control circuit isillustrated in FIG. 35 . This first exemplary embodiment uses adouble-throw, double pole switch 1200. The switch 1200 is normallyspring-biased to a center position in which both poles are off. Themotor M illustrated can, for example, represent the stapling motor 210.As can be seen, the power-on switch 1210 must be closed to turn on thedevice. Of course, this switch is optional. When a forward movement ofthe motor M is desired, the switch 1200 is placed in the right positionas viewed in FIG. 35 , in which power is supplied to the motor to runthe motor in a first direction, defined as the forward direction herebecause the “+” of the battery is connected to the “+” of the motor M.In this forward switching position, the motor M can power the blade 1060in a distal direction. Placement of an appropriate sensor or switch toindicate the forward-most desired position of the blade 1060 or the sled102 can be used to control a forward travel limit switch 1220 thatinterrupts power supply to the motor M and prevents further forwardtravel, at least as long as the switch 1220 remains open. Circuitry canbe programmed to never allow this switch 1220 to close and complete thecircuit or to only allow resetting of the switch 1220 when a new staplecartridge, for example, is loaded.

When a reverse movement of the motor M is desired, the switch 1200 isplaced in the left position as viewed in FIG. 35 , in which power issupplied to the motor to run the motor in a second direction, defined asthe reverse direction here because the “−” of the battery is connectedto the “+” of the motor M. In this reverse switching position, the motorM can power the blade 1060 in a proximal direction. Placement of anappropriate sensor or switch to indicate the rearward-most desiredposition of the blade 1060 or the sled 102 can be used to control arearward travel limit switch 1230 that interrupts power supply to themotor M and prevents further rearward travel, at least as long as theswitch 1230 remains open. It is noted that other switches (indicatedwith dotted arrows) can be provided in the circuit to selectivelyprevent movement in either direction independent of the limit switches1220, 1230.

It is noted that the motor can power the gear train with a significantamount of force, which translates into a high rotational inertia. Assuch, when any switch mentioned with respect to FIGS. 34 and 35 is usedto turn off the motor, the gears may not just stop. Instead, therotational inertia continues to propel, for example, the rack 217 in thedirection it was traveling when power to the motor was terminated. Suchmovement can be disadvantageous for many reasons. By configuring thepower supply and motor appropriately, a circuit can be formed tosubstantially eliminate such post-termination movement, thereby givingthe user more control over actuation.

FIG. 36 illustrates an exemplary embodiment where the motor (forexample, stapling motor 210) is arrested from further rotation whenforward or reverse control is terminated. FIG. 36 also illustratesalternative embodiments of the forward/reverse control and of themulti-stage power supply. The circuit of FIG. 36 has a motor arrestsub-circuit utilizing a short-circuit property of an electrical motor.More specifically, the electrical motor M is placed into a short-circuitso that an electrically generated magnetic field is created inopposition to the permanent magnetic field, thus slowing thestill-spinning motor at a rate that substantially preventsinertia-induced over-stroke. To explain how the circuit of FIG. 36 canbrake the motor M, an explanation of the forward/reverse switch 1300 isprovided. As can be seen, the forward/reverse switch 1300 has threepositions, just like the switch 1200 of FIG. 35 . When placed in theright position, the motor M is actuated in a forward rotation direction.When placed in the left position, the motor M is actuated in a rearwardrotation direction. When the switch 1300 is not actuated—as shown inFIG. 36 —the motor M is short circuited. This short circuit isdiagrammatically illustrated by the upper portion of the switch 1300. Itis noted that the switching processes in a braking switch is desired totake place in a time-delayed manner, which is also referred to as abreak-before-make switching configuration. When switching over fromoperating the motor M to braking the motor M, the double-pole, doublethrow portion of the forward/reverse switch 1300 is opened before themotor short circuit is effected. Conversely, when switching over frombraking the motor M to operating the motor M, the short circuit isopened before the switch 1300 can cause motor actuation. Therefore, inoperation, when the user releases the 3-way switch 1300 from either theforward or reverse positions, the motor M is short-circuited and brakesquickly.

Other features of the circuit in FIG. 36 have been explained with regardto FIG. 35 . For example, an on/off switch 1210 is provided. Alsopresent is the power lock-out switch 1100 that only powers the motorwith one power cell 602′ in a given portion of the actuation (which canoccur at the beginning or at any other desired part of the stroke) andpowers the motor M with all of the power cells 602 (here, for example,six power cells) in another portion of the actuation.

A new feature of the reverse and forward limit switches 1320, 1330prevents any further forward movement of the motor M after the forwardlimit switch 1320 is actuated. When this limit is reached, the forwardlimit switch 1320 is actuated and the switch moves to the secondposition. In this state, no power can get to the motor for forwardmovement but power can be delivered to the motor for reverse movement.The forward limit switch can be programmed to toggle or be a one-timeuse for a given staple cartridge. More specifically, the switch 1320will remain in the second position until a reset occurs by replacing thestaple cartridge with a new one. Thus, until the replacement occurs, themotor M can only be powered in the reverse direction. If the switch ismerely a toggle, then power can be restored for additional furthermovement only when the movement has retreated the part away fromactuating the switch 1320.

The reverse limit switch 1330 can be configured similarly. When thereverse limit is reached, the switch 1330 moves to the second positionand stays there until a reset occurs. It is noted that, in thisposition, the motor M is in a short-circuit, which prevents motormovement in either direction. With such a configuration, the operationof the stapler can be limited to a single stroke up to the forward limitand a single retreat up to the rear limit. When both have occurred, themotor M is disabled until the two switches 1320 are reset.

Referring now to the figures of the drawings in detail and first,particularly to FIGS. 37 to 40 thereof, there is shown an exemplaryembodiment of an electric surgical device 1000, which, in thisembodiment, is an electric surgical linear stapler. FIG. 37 shows theleft side of the device 1000 with the handle's outer shell 1001 and 1002removed. Similarly, FIG. 39 shows the right side of the device 1000 withthe handle's outer shell removed. The two halves of the outer shell 1001and 1002 are only shown in FIGS. 63 to 66 to allow for clear viewing ofthe internal assemblies. Also not shown in these and the subsequentfigures is the end effector. An exemplary embodiment of a linearstapling end effector is described in detail in the family of co-ownedand co-pending patent applications including U.S. Provisional PatentApplication No. 60/702,643 filed Jul. 26, 2005, 60/760,000 filed Jan.18, 2006, and 60/811,950 filed Jun. 8, 2006, and U.S. patent applicationSer. No. 11/491,626 filed Jul. 24, 2006, Ser. No. 11/540,255 and Ser.No. 11/541,105 both filed Sep. 29, 2006, and Ser. No. 11/844,406 filedAug. 24, 2007. The entire disclosure of this family of applications ishereby incorporated herein by reference in its entirety.

FIG. 38 shows the mechanical assembly of the device 1000 with theleft-side frames 1010 removed. FIG. 40 , in comparison, shows themechanical assembly both the left- and right-side frames 1010, 1020removed.

FIG. 37 shows the gear cover plate 1105, under which are the first-,second-, and third-stage gears 1110, 1120, 1130 of the motortransmission assembly. Also appearing in FIG. 37 is the end effectorclosing assembly 1400. This end effector closing assembly 1400 will beexplained in greater detail with regard to FIGS. 59 to 60 .

FIGS. 37 to 38 also show the electric power and power controlassemblies. The electric power assembly 1500 in this exemplaryembodiment is a removable battery pack containing one or more batteries1510. As set forth above, one exemplary power supply is a seriesconnection of between four and six CR123 or CR2 power cells. Here, thereare six batteries 1510. One of these batteries 1510 a, the one on theupper left in FIG. 37 , is placed in an electrically disconnectableconfiguration so that power can be supplied selectively to the motor1520 through either the single battery 1510 a or the entire set of sixbatteries 1510. This is beneficial in applications where only a smallamount of power is needed or where full torque is desired to beprohibited. One such prohibition is mentioned above with regard tomoving the staple sled or blade past the lock-out. The exemplary circuitonly connects this one cell 1510 a to the motor 1520 during the firstpart of the stapling/cutting stroke and, in the second part of thestapling/cutting stroke, all of the cells 1510, 1510 a in the powersupply are connected to the motor 1520. See FIG. 34 .

The power supply control assembly 1600 in the exemplary embodiment takesthe form of a rocker switch 1610. In one actuated direction of therocker switch 1610, the motor 1520 is caused to rotate in a firstdirection, for example, forward, and in the other actuated direction ofthe rocker switch 1610, the motor 1520 is caused to rotate in anopposite second direction, for example, reverse.

The electrically powered drive train in the exemplary embodiment is usedto operate one feature of a linear cutter/stapler. Here, the drive trainis being used to actuate the stapling/cutting feature. To do this, thedrive train is connected to a linear actuator 1700, which, in thepresent embodiment, is in the form of a toothed rack that translatesdistally and proximally along a rack guide 1720. As shown in FIG. 38 ,the rack 1700 is in a relatively proximal position. To minimize the sizeof the shell 1001, 1002 at the proximal end (right side of FIG. 38 ),the rack 1700 has a pivoting portion 1710 that pivots freely in thedownward direction (as viewed in FIG. 38 ) when the pivoting portion1710 is not contained within the rack guide 1720. As the rack 1700 movesdistally (to the left in FIG. 38 ), the bottom of the pivoting portion1710 contacts the proximal end of the rack guide 1720 and is caused topivot upward to a position that is substantially coaxial with theremainder of the rack 1700 due to the shape of the rack guide 1720. Theproximal end of the rack guide 1720 is seen in FIG. 41 .

The teeth 1702 of the rack 1700 are shaped to interact with a finalstage of the drive train in a rack-and-pinion configuration. Whilevarious features of the drive train are visible in virtually all ofFIGS. 37 to 47 , the explanation of the drive train is easily seen withparticular reference to FIGS. 43 and 46 . It is noted here that some ofthe transmission stages shown in many of the figures have no teeth. Thisis because the gears are merely diagrammatic representations of aparticular exemplary embodiment. Thus, the lack of teeth, or even thenumber or size of teeth present, should not be taken as limiting orfixed. Additionally, many of the gears illustrated are shown with acentral band located inside the teeth. This band should not beconsidered as part of the device 1000 and is, merely, a limitation ofthe software used to create the figures of the instant application.

The explanation of the drive train starts from the motor 1520. An outputgear 1522 of the motor 1520 is connected to the first, second, and thirdstages 1110, 1120, 1130 of the transmission. The third stage 1130 iscoupled to the final gear present on the left side of the device 1000.This couple is difficult to view in all of the figures because of itsinterior location. FIGS. 55 to 56 , however, show the coupling of thethird stage 1130 to the fourth stage, cross-over gear 1140. As mentionedabove, the output of the third stage 1130 is only diagrammaticallyillustrated—as a cylinder without teeth. Continuing to refer to FIG. 46, the cross-over gear 1140 is rotationally coupled to a fourth stageshaft 1142, which shaft 1142 crosses over the rack 1700 from the leftside of the device 1000 to the right side. The right side of the shaft1142 is not directly coupled in a rotational manner to any of the gearson the right side. Instead, it rotates inside a shaft bearing 1144 thatfits inside a corresponding pocket within the right side frame 1020,which frame 1020 is removed from the view of FIG. 46 to allow viewing ofthe right side drive train.

A castle gear 1146 (shown by itself in FIG. 53 ) is positioned on thecross-over shaft 1142 to be rotationally fixed therewith butlongitudinally translatable thereon. To permit such a connection, theshaft 1142 has a non-illustrated interior slot in which is disposed anon-illustrated pin that passes through two opposing ports 11462 of thecastle gear 1146. By fixedly securing the pin to the castle gear 1146,rotation of the shaft 1142 will cause a corresponding rotation of thecastle gear 1146 while still allowing the castle gear 1146 to freelytranslate along the longitudinal axis of the shaft 1142, at least to theextent of the slot in the shaft 1142. As can be seen in FIG. 46 , theright-side castellations 11464 of the castle gear 1146 are shaped to fitbetween corresponding castellation slots 11482 on the left-side of afourth stage pinion 1148, which is illustrated by itself in FIG. 54 .Because the castle gear 1146 is required to mate securely with thefourth stage pinion 1148, a right-side biasing force F is needed. Tosupply this bias, a non-illustrated compression spring, for example, canbe provided to have one end contact the right face of the cross-overgear 1140 and the other opposing end contact the left face of a centralflange 11468, which projects radially away from the outer cylindricalsurface of the castle gear 1146. (This flange 11468 will be described inmore detail below with respect to the manual release feature of thedevice 1000.) Any other similarly functioning bias device can be usedinstead of the exemplary spring. Such a configuration allows the castlegear 1146 to be selectively rotationally engaged with the fourth stagepinion 1148. More specifically, when the castle gear 1146 is not actedupon by any force other than the force F of the bias device, thecastellations 11464 will be mated with the castellation slots 11482 andany rotation of the shaft 1142 will cause a corresponding rotation ofthe fourth stage pinion 1148. However, when a force opposing andovercoming the bias F is applied, the castellations 11464 exit thecastellation slots 11482 and any rotation of the shaft 1142 has noeffect on the fourth stage pinion 1148. It is this selective engagementthat allows a manual release to occur. Before such release is explained,the right side drive train is described.

The fourth stage pinion 1148 is directly engaged with a fifth stage 1150of the drive train, which has a fifth stage shaft 1152, a fifth stageinput gear 1154 rotationally fixed to the fifth stage shaft 1152, and afifth stage pinion 1156, also rotationally fixed to the fifth stageshaft 1152. The teeth of the fifth stage pinion 1156 are directlycoupled to the teeth 1702 of the rack 1700. Thus, any rotation of thefifth stage input gear 1154 causes a corresponding rotation of the fifthstage pinion and a longitudinal movement of the rack 1700. As viewed inthe exemplary embodiment of FIG. 46 , a clockwise rotation of the fifthstage input gear 1154 causes a proximally directed movement of the rack1700 (retract) and a counter-clockwise rotation of the fifth stage inputgear 1154 causes a distally directed movement of the rack 1700 (extend).

Based upon the above connection of the five stages of the drive train,rotation of the motor shaft in one direction will cause a longitudinalmovement of the rack 1700, but only when the castle gear 1146 is engagedwith the fourth stage pinion 1148. When the castle gear 1146 is notengaged with the fourth stage pinion 1148, rotation of the motor has noeffect on the rack 1700. It is in this uncoupled state of the two gears1146, 1148 that a manual release of the rack 1700 becomes possible.

In operation of the device 1000, the rack 1700 moves distally (extends)to actuate some part of an end effector. In the embodiment of a linearsurgical stapling/cutting device, when the rack 1700 moves distally, thesled (carrying the stapling actuator and cutting blade) that causes bothstapling and cutting to occur is moved distally to effect both staplingand cutting. Because the tissue placed between the jaws of the endeffector is different in virtually every surgical procedure, a physiciancannot anticipate times when the sled will be jammed or stuck for anyreason. In a jammed case, the sled will need to be retracted distallywithout use of the motor. There also exists the possibility of a powerloss or the possibility that the motor fails in a catastrophic fashionrendering the output shaft fixed. If this occurred when the sled was ina distal position, the jaws of the end effector would be held shut onthe tissue therebetween and, consequently, the sled would have to bemoved proximally before the jaws could be opened and the tissue could bereleased. In such a case, the rack 1700 will need to be retracteddistally without use of the motor. To effect this desired function,there is provided a manual release assembly 1800.

In each of FIGS. 37 to 44, 55, 59 to 62 , the manual release lever 1810is in the un-actuated (e.g., down) position. In FIGS. 45 and 57 , themanual release lever 1810 is in an intermediate position. And, in FIGS.46, 47, 56, and 58 , the manual release lever 1810 is approximately in afully actuated (e.g., up) position.

When the manual release lever 1810 is in the un-actuated position, ascan be seen in FIG. 44 , the castle gear 1146 is engaged with the fourthstage pinion 1148. Thus, any rotation of the output gear 1522 of themotor 1520 causes movement of the rack 1700. The fourth stage pinion1148 is not only directly connected to the fifth stage input gear 1154,however. It is also directly connected to a first stage release gear1820, which, in turn, is directly connected to a second stage releasegear 1830. Thus, any rotation of the fourth stage pinion 1148necessarily causes a rotation of the second stage release gear 1830 (thedirection of which being dependent upon the number of gearstherebetween). If the axle of this gear 1830 was directly connected tothe manual release lever 1810, the lever 1810 would rotate every timethe fourth stage pinion 1148 rotated. And, if the fourth stage pinion1148 rotated more than one revolution, the lever 1810 could possibly becaused to rotate through a full 360 degree revolution. As expected, thisdoes not occur due to the presence of a one-way gear assembly couplingthe manual release lever 1810 to the second stage release gear 1830 (seeexplanation of FIG. 48 below). It is noted that the first stage releasegear 1820 has a toothed shaft 1822 extending coaxially therefrom. Thistoothed shaft 1822 is directly coupled to an indicator wheel 1840. Ascan be seen on the right surface of the wheel 1840, there is a curvedshape linearly expanding about the axis of the wheel 1840 and having adifferent color from the remainder of the surface. When coupled with thewindow 1004 present on the right side shell 1002 (see FIGS. 64 to 65 ),the colored shape becomes more and more visible in a linearmanner—corresponding to a linear distance of the rack 1700 traveled fromthe fully proximal (e.g., retracted) position.

The one-way gear assembly coupling the manual release lever 1810 to thesecond stage release gear 1830 is shown in FIG. 48 . This assembly isformed by providing a ratchet gear 1850 centered at a pivot point of thelever 1810 and extending an axle 1852 of the ratchet gear 1850 into andthrough a center bore 1832 of the second stage release gear 1830. Withthe axle 1852 fixed to the bore 1832 of the second stage release gear1830 in this way, any rotation of the second stage release gear 1830causes a corresponding rotation of the ratchet gear 1850. But, merelyhaving this ratchet gear 1850 rotate with the second stage release gear1830 does not, by itself, assist with a manual release of the rack 1700when the motor 1520 is not powering the drive train.

To create the manual release function, two manual releasing items arepresent. The first item is a device that uncouples the right side geartrain from the left side gear train and motor. This prevents the manualrelease from having to overcome the resistance offered by both the motor1520 and the gears of the left side train when the manual release isactuated. The uncoupling occurs when the castle gear 1146 separates fromthe fourth stage pinion 1148. To cause this uncoupling, a cam plate 1860is disposed between the ratchet gear 1850 and the second stage releasegear 1830 and is rotationally fixed to the axle 1852. The cam plate 1860is shown by itself in FIG. 52 . The cam plate 1860 is provided with aramped cam surface 1862 that is positioned to interact with the centralflange 11468 of the castle gear 1146. Interaction of the cam plate 1860with the central flange 11468 can be seen in the progression of FIGS. 44to 47 and in FIGS. 57 to 58 .

In FIG. 44 , the manual release lever 1810 is in an unactuated position,which means that it is desired to have the castle gear 1146 rotationallycoupled with the fourth stage pinion 1148. In this way, any rotation ofthe motor 1520 will be translated into a rotation of the fourth stagepinion 1148 and a movement of the rack 1700. In FIGS. 45 to 47 and 57 to58 , the manual release lever 1810 is in one of a few actuatedpositions, each of which is illustrated as being sufficient to rotatethe cam plate 1860 to have the ramped cam surface 1862 contact thecentral flange 11468 of the castle gear 1146 and force the castle gear1146 towards the left side sufficient to separate the castellations11464 from the castellation slots 11482 of the fourth stage pinion 1148.In this position, the castle gear 1146 is rotationally uncoupled fromthe fourth stage pinion 1148. Thus, any rotation of the motor 1520 (orthe gears of the left side train) will be entirely independent from theright side gear train, thus preventing any movement of the rack 1700based upon rotation of the motor 1520.

After the right side gear train become rotationally independent from theright side motor and gear train, to have a manual rack release function,the rack 1700 needs to be moved in the proximal direction. To supplythis movement, a second of the two above-mentioned manual releasingitems is provided. This second item interacts with the teeth 1832 of theratchet gear 1850 so that a counter-clockwise rotation of the manualrelease lever 1810 (when viewed from the right side of the device 1000)causes the ratchet gear 1850 to spin in a counter-clockwisedirection—this direction is desired in the illustrated embodimentbecause such rotation causes a clockwise rotation of the fifth stagepinion 1156—a rotation that corresponds to proximal movement (e.g.,retraction) of the rack 1700. To control the ratchet gear 1850 with thiscounter-clockwise lever 1810 movement, there is provided a ratchet pawl1870 that is rotatably mounted on a locking boss 1814 of the lever 1810.This configuration is best illustrated in FIG. 48 . A non-illustratedleaf spring is secured in a spring channel 1816 of the lever 1810 tobias the pawl 1870 in a direction D towards the ratchet gear 1850. It isnoted that if the pawl 1870 were not restrained in some way, however,the pawl 1870 would always contact the teeth 1852 of the ratchet gear1850 and prevent any clockwise rotation of the gear 1850—which occurs inthe present embodiment when the castle gear 1146 and the fourth stagepinion 1148 are engaged with one another (see, i.e., FIG. 44 ) androtate together. To prevent this condition, as shown in FIGS. 44 and 55, the distal end of the pawl 1870 has a widened portion 1872 thatextends out from the pawl cavity 1818 towards the second stage releasegear 1830. With the presence of a second cam plate 1880 between thesecond stage release gear 1830 and the cam plate 1870, a pawl cam 1882can be positioned to contact the bottom surface of the widened portion1872 and retain the pawl 1870 in the pawl cavity 1818 (by providing aforce in a direction opposite to direction D and against bias of theleaf spring) when the lever 1810 is in a home or unactuated position.This contact between the pawl 1870 and the pawl cam 1882 is shown inFIGS. 44 and 55 . Thus, when the lever 1810 is not actuated, the pawl1870 has no contact with the teeth 1852 of the ratchet gear 1850. Incontrast, when the manual release has rotated past a position sufficientto separate the ratchet gear 1850 from the fourth stage pinion 1148, thebottom surface of the pawl 1870 no longer contacts the pawl cam 1882 ofthe non-rotating second cam plate 1880 and is, therefore, free to movein the direction D (caused by the biasing force of the leaf spring) toengage the teeth 1852 of the ratchet gear 1850 when rotatingcounter-clockwise. Thus, when rotating clockwise, the pawl 1870 ratchetsagainst the top surfaces of the teeth 1852.

After about fifteen degrees of travel of the lever 1810, for example,the pawl 1870 no longer is in contact with the pawl cam 1882 and thecastellations 11464 of the castle gear 1146 are no longer engaged withthe castellation slots 11482 of the fourth stage pinion 1148. At thispoint, the pawl 1870 is permitted to move towards the axle 1852 andengages one of the teeth 1852 of the ratchet gear 1850. Furthercounter-clockwise movement of the lever 1810 turns the ratchet gear 1850correspondingly, which causes a corresponding counter-clockwise rotationof the second stage release gear 1830. In turn, rotation of the secondstage release gear 1830 causes clockwise rotation of the first stagerelease gear 1820, counter-clockwise rotation of the fourth stage pinion1148, and clockwise rotation of the fifth stage input gear 1154,respectively. As indicated above, clockwise rotation of the fifth stageinput gear 1154 causes proximal movement of the rack 1700—the desireddirection of movement during a manual release of the end effectorfeature connected to the rack 1700. As the lever 1810 is released, areturn bias 1890 forces the lever 1810 back to its unactuated position(see FIG. 44 ), which causes the pawl cam 1882 to return the pawl 1870to its upper position in the pawl cavity 1818 where it is disengagedfrom the teeth 1852 of the ratchet gear 1850. It is noted that contactbetween the pawl cam 1882 and the lower surface of the widened portion1872 is made smooth by shaping the respective top front and top rearsurfaces of the pawl cam 1882 and bottom front and bottom rear surfacesof the widened portion 1872. It is further noted that the return bias1890 is shown in FIGS. 46, 57 , and 58, for example, as a coil spring,one end of which is wrapped around a bolt secured to the lever 1810 andthe other opposing end being a shaft that is secured to a portion of theshell 1001, 1002, illustrated in FIGS. 63-66 . The opposing shaft of thecoil spring 1890 moves in the illustrations only due to the limitationsof the drawing program. In actuality, this movement does not occur.

As discussed above, one exemplary embodiment of the end effector for thedevice 1000 includes a set of jaws that close down upon tissue disposedtherebetween and a stapler/cutter to secure together each of two sidesof the tissue as it is being cut. The manual release described above canbe coupled to the stapler/cutter and the end effector closing assembly1400 can be coupled to the jaws to close the jaws together whenactuated. FIGS. 59 to 60 illustrate one exemplary embodiment of thecouple between the jaws and the end effector closing assembly 1400.Here, the end effector closing assembly 1400 is comprised of a handle1410 having a lever support 1412 and pivoting about a handle pivot 1414.The lever support 1412 is pivotally connected to a first end of a link1420. A second opposing end of the link 1420 is pivotally connected to aslider shaft 1430. The end effector shaft assembly 1900 includes anouter shaft 1910 and an inner shaft 1920. The inner shaft 1910 islongitudinally fixed to the frames 1010, 1020 and to the lower jaw ofthe end effector and, therefore, is the longitudinally fixed componentof the end effector. The outer shaft 1920 is connected about the innershaft 1910 and longitudinally translates thereon. The upper jaw of theend effector pivots in relation to the lower jaw. To cause the pivoting,the outer shaft 1920 is extended from a proximal position, shown in FIG.59 , to a distal position, shown in FIG. 60 . Because the outer shaft1920 surrounds the inner shaft, a portion (for example, an upperportion) contacts the proximal end of the open upper jaw, which is at aposition proximal of the upper jaw pivot. As the outer shaft 1920 movesfurther distal, the upper jaw cannot translate distally because of thefixed pivot position, but can rotate about that pivot. Accordingly, theupper jaw closes upon the lower, longitudinally fixed jaw. Simply put,and as can be seen in the progression from FIG. 59 to FIG. 60 , when thehandle 1410 is moved towards the electric power assembly 1500, theslider 1430 moves in the longitudinal direction from the proximalposition of FIG. 59 to the distal position of FIG. 60 . This prior artjaw assembly is present on a linear stapler manufactured by EthiconEndo-Surgery under the trade name Echelon EC60.

It is noted that this exemplary configuration of the end effector shaftassembly 1900 is opposite to the end effector actuation shown in familyof co-pending patent applications mentioned above, including applicationSer. No. 11/844,406, filed Aug. 24, 2007. As shown in this applicationin FIGS. 39 and 40 , as the lower jaw/staple cartridge holder 1030 istranslated in the proximal direction over gap 1031, the upper anvil 1020is caused to pivot downward because the proximal upper edge of the upperanvil 1020 is being pressed against the longitudinally fixed drum sleeve1040.

Various prior art linear staplers, such as the Echelon EC60 mentionedabove, use the same end effector and shaft. Therefore, it is desirableto have those prior art end effector shaft assemblies be able to fitinside the device 1000. This is accomplished by configuring the left andright side frames 1010, 1020 as shown in FIGS. 61 to 62 , for example.The frames 1010, 1020 are formed with one side (the upper side) open asshown in FIG. 62 . In this configuration, the proximal end of the innershaft 1910 prior art end effector shaft assembly can simply side inbetween respective tabs 1012, 1022 to longitudinally fix the inner shaft1910 (and, thus, the entire assembly) therein and transversely fix theinner shaft 1910 therebetween in all radial directions except for thedirection in which the inner shaft 1910 was inserted into the openingbetween the frames 1010, 1020. To close off this opening, a shaft plug1930 is secured between the tabs 1012, 1022, for example, with a bolt,as shown in FIG. 61 . In another alternative embodiment, the shaft plug1930 can be entirely disregarded by extending the distal ends of theleft and right frames 1010, 1020 and shaping them, in a clam-shelldesign, to be secured around the inner shaft 1910 when placed together.

The foregoing description and accompanying drawings illustrate theprinciples, preferred embodiments and modes of operation of the systems,apparatuses, and methods disclosed herein. More specifically, theoptimized power supply, motor, and drive train according to the systems,apparatuses, and methods disclosed herein have been described withrespect to a surgical stapler. However, the systems, apparatuses, andmethods disclosed herein should not be construed as being limited to theparticular embodiments discussed above. Additional variations of theembodiments discussed above will be appreciated by those skilled in theart as well as for applications, unrelated to surgical devices, thatrequire an advanced power or current output for short and limiteddurations with a power cell having a limited power or current output. Asis shown and described, when optimized according to the systems,apparatuses, and methods disclosed herein, a limited power supply canproduce lifting, pushing, pulling, dragging, retaining, and other kindsof forces sufficient to move a substantial amount of weight, forexample, over 82 kg.

The above-described embodiments should be regarded as illustrativerather than restrictive. Accordingly, it should be appreciated thatvariations to those embodiments can be made by those skilled in the artwithout departing from the scope of the invention as defined by thefollowing claims.

What is claimed is:
 1. A surgical device, comprising: a surgical endeffector; an actuation assembly having a part operable to move between:a first position; and a second position; an electrically-powered motor;a transmission mechanically connecting the motor to the part and beingoperable to selectively displace the part between the first and secondpositions when the motor is operated; and a manual release mechanicallycoupled to the transmission to selectively interrupt the transmissionand, during interruption, displace the part towards the first positionindependent of operation of the motor.
 2. The surgical device accordingto claim 1, wherein the transmission is operable to selectively displacethe part to any point between the first position and the second positionwhen the motor is operated.
 3. The surgical device according to claim 1,further comprising a controller electrically connected to the motor andselectively operating the motor.
 4. The surgical device according toclaim 1, wherein the surgical end effector is a stapling end effector.5. The surgical device according to claim 1, wherein the manual releaseis mechanically disposed in the transmission.
 6. A surgical device,comprising: a surgical end effector; an actuation assembly having a partoperable to move between: a starting position; and an actuated positionin which the part actuates the surgical end effector; anelectrically-powered motor; a transmission mechanically connecting themotor to the part and being operable to selectively displace the partbetween the starting and actuated positions when the motor is operated;and a manual release mechanically coupled to the transmission toselectively interrupt the transmission and, during interruption,displace the part towards the starting position independent of operationof the motor.
 7. The surgical device according to claim 6, wherein thetransmission is operable to selectively displace the part to any pointbetween the starting position and the actuated position when the motoris operated.
 8. The surgical device according to claim 6, furthercomprising a controller electrically connected to the motor andselectively operating the motor.
 9. The surgical device according toclaim 6, wherein the surgical end effector is a stapling end effector.10. The surgical device according to claim 6, wherein the manual releaseis mechanically disposed in the transmission.
 11. A method for operatinga surgical instrument, which comprises: mechanically coupling a manualrelease to a transmission of the surgical instrument, the surgicalinstrument having a surgical end effector and an actuation assembly,wherein: the transmission translates movement of an electrically-poweredmotor of the device to movement of a part of the actuation assembly; andthe part is operable to move between a first position and a secondposition; and selectively interrupting the transmission with the manualrelease to move the part towards the first position independent ofoperation of the motor.
 12. The method according to claim 11, wherein:the first position is a starting position; and the second position is anactuated position in which the part actuates the surgical end effector.13. The method according to claim 11, wherein the transmission isoperable to selectively displace the part to any point between the firstposition and the second position when the motor is operated.
 14. Themethod according to claim 11, wherein the surgical instrument furthercomprises a controller electrically connected to the motor andselectively operating the motor.
 15. The method according to claim 11,wherein the surgical end effector is a stapling end effector.